Junior Guerra has had an up-and-down season, which will deserve more analytical scrutiny once the season closes. Brewers fans largely wrote off Guerra after the righty experienced a forearm injury in July (on DL July 14-24), which preceded a truly dreadful stretch of baseball. Returning from the disabled list, Guerra started eight games, ultimately working 37.3 innings while allowing 38 runs (!!!) and a 32 strike out / 16 walk / 8 homer / 1.08 Groundball:Flyball peripheral performance. At this point, the Brewers replaced Guerra in the rotation with newly acquired southpaw Gio Gonzalez, himself looking for some redemption in a new locale.

Guerra’s fall was shocking in part because the righty maintained solid Runs Prevented throughout the year. On May 31, the splitter pitcher averaged approximately Nine Runs Prevented; that swelled to approximately 11 Runs Prevented through July, before returning to approximately Nine Runs Prevented on August 12 and plummeting to -1.3 Runs Prevented by August 24. Guerra bottomed out at an average of -9.0 Runs Prevented on September 9, meaning that the righty boasts one of the Top 10 Runs Prevented “declines” during the 2018 season:

What is notable, however, is that despite Guerra’s large decline from May through September, the righty ultimately provided (approximately) average production throughout the season. Ironically, Gio Gonzalez matches this trend for Guerra as well, as the lefty averaged approximately Four Runs Prevented for the Nationals despite falling to below average production by the time he was traded to Milwaukee.

So, the Brewers entered a playoff stretch run by moving one formerly productive starting pitcher into the rotation at the expense of another formerly productive starting pitcher. Yet, Craig Counsell provided Guerra a couple of opportunities to define his relief role while working in close deficits on September 11 and September 15, and the righty also made another appearance during last night’s series closing victory against the Reds.

I’ve dreamed on a Guerra relief role since the beginning, considering the righty’s command stature and splitter as two of the reasons that the righty might morph from a starting pitcher into a reliever. What is fascinating, however, is that while Guerra is absolutely lights out over 3.7 relief innings thus far (5 K / 0 BB / 0 HR / 1.33 GB:FB), that formerly elite splitter is nowhere to be seen. In fact, according to Brooks Baseball, entering Wednesday night’s match-up against the Reds, the righty had almost exclusively worked fastball / breaking ball in relief. At the time of this writing, Brooks Baseball data had yet to reflect Guerra’s last outing, but raw Gameday Play-By-Play suggests that Guerra was once more a two-pitch pitcher.

What is especially stunning about Guerra moving to a fastball / breaking ball relief profile is that the hurler is not even using his slider. According to Brooks Baseball, Guerra’s velocity, vertical movement, and horizontal movement profile on his breaking ball matches his previous “curveball,” rather than his well-known “slider.” Here’s how Guerra’s pitch profile looked as a starting pitcher in 2018:

To emphasize just how different this new version of Guerra looks from the old Guerra, here’s how Brooks Baseball classified his relief work in September 2017:

While it is too early to make note of any velocity changes on the fastball based on standard deviation on Guerra’s September fastballs as a starter and a reliever, it is worth diving into the sharp arsenal change exhibited by Guerra. According to Brooks Baseball, Guerra’s fastball / breaking ball blend is producing more whiffs and groundballs on his fastball than his starting pitching usage of the pitch, while the “curveball” effectively is acting like a splitter in terms of whiffs and groundballs. Notably, this combination of pitches finds Guerra working in entirely new areas of the strike zone with his fastball compared to his previous usage, with the caveat that this is an extremely small number of pitches to draw any meaningful conclusions.

With this curveball offering, however, Guerra has already thrown nearly as many pitches as a reliever compared to his entire time as a starter in 2018, and here it is worth noting that Guerra is scattering the pitch more evenly across the bottom of the strike zone while also moving it away from the upper-armside (inside against a righty bat) area of the zone:

Ultimately, I do not think assessing Guerra’s arsenal shift as a reliever is “much ado about nothing,” as the righty is suddenly answering a crucial question entering potential playoff series: who can help to stretch out close deficits? Granted, in the playoffs, pitchers like Jeremy Jeffress and Josh Hader will probably experience higher workloads. However, since the Brewers seemingly base Hader’s workload off of his recovery time, adding another reliever that can effectively work a couple of frames is extremely important (especially as starting pitchers work shorter outings as the season winds down). It cannot be understated that Guerra is also working for his future with Milwaukee, a club that is also arguably designing an unorthodox pitching staff that is based around systemic runs prevention rather than standard 1-through-5 starting pitching assessments. This is undoubtedly one reason Guerra had a job to begin with, and undoubtedly one reason the Brewers gave the righty every chance to succeed as a starter. Guerra the reliever could still potentially fit into a 2019 pitching staff that may double down on amorphous roles after general 2018 Runs Prevented success.

Now, perhaps it is time to dream bigger on that relief role for the stretch run, potentially the playoffs, and for 2019; in this regard, it is also time to scrutinize a relief role for Guerra. If it can be stated that Guerra exhausted the utility of his fastball / splitter / slider arsenal in Milwaukee, a new look at a hard, rising fastball and slightly slower curve combination could find the age-33 hurler staying on for at least one more go ’round. In this regard, it’s interesting to think about the pitchers in Milwaukee that have benefited from learning Guerra’s splitter, and now view the righty as a beneficiary of Pitching Coach Derek Johnson’s curveball instruction (recall that this is the pitch that revitalized Jimmy Nelson and Chase Anderson). When one role ends for a pitcher, a new pitch can present a new role; while this should not be viewed as magical thinking, nor a fail-proof development, for now it should be viewed as a new opportunity for Guerra to bolster Milwaukee’s high leverage relief group.

Related: MLB Runs Prevented Spreadsheet (May 31), by Baseball Prospectus Milwaukee
https://docs.google.com/spreadsheets/d/1VpFojsjq2PZMfcHQmTvXxGeMxirSqyMACnKQ7oxjx3M/edit?usp=sharing

Batting Inefficiencies

For the season, however, a few nearly inexplicable inefficiencies exist among Brewers batting splits. Overall, the offense remains moderately below average, but the batting performances by position are worse than those assessed by spot in the order. This, on the whole, is a good thing, as it suggests that even though the club is not hitting well, Manager Craig Counsell is using the batting order to create efficient production.

Yet, the production does not occur at the positions in the order one would expect. The following table uses “RRBI,” my favorite “quick and dirty” at-a-glance statistic that assesses the harmonic mean between Runs Scored and Runs Batted In (to very quickly assess team run distribution within their specific environment), and simple OPS. Both statistics are corrected for 2018 National League and multi-year park factor (Baseball Reference). While RBI is not necessarily a valuable stat in terms of predictive function, or even a descriptive metric of actual value, taking the harmonic mean between R and RBI allows one to understand the development of run production throughout a batting order in terms that are scaled to the team. Think of “RRBI” as a statistic for “uneven development” translated into baseball terms: uneven terrain between expected value, peripheral and predictive metrics, and actual run distribution matters in the context of attempting to win baseball games by scoring runs.

By isolating individual players, instead of looking at each position and batting order on a teamwide scale, two key inefficiencies emerge: First, the time-share in the outfield between Ryan Braun, Lorenzo Cain, Domingo Santana, and Christian Yelich appears to be yielding inefficient results; Second, the frigid starts for many Brewers depth players created a wider chasm between “starting” and “bench” players than would have been expected. One might raise a third issue with batting Lorenzo Cain in the lead-off position, as although the center fielder’s performance is fantastic, the lead-off spot typically saps RBI opportunities and therefore may unduly discredit Cain for aspects of his run performance.

What is interesting to note here is that some of the coldest bats in the order are not hurting the team as much as fans might typically expect. For example, the slow start by Santana and the veritable black hole that is the sixth batting order spot have hurt the Brewers production much more so than Orlando Arcia (who actually gains “efficiency” by batting eighth; by position, his bat is second worst, but the club gained almost two runs by batting Arcia, Saladino, and Sogard eighth). Blending position and batting order strength against the National League expectations, however, a sample “maximum efficiency” batting order does not appear feasible whatsoever:

The Inevitable Pitching Correction?

In terms of pitching, the staff is much less puzzling than the bats, which seem to be a group prone to wild variations of extreme production. Available for sharing above, the “Runs Prevented” spreadsheet showcases that the Brewers bullpen is so elite that Jeremy Jeffress and Josh Hader rank in the Top 25 for average runs prevented among all pitchers (not simply relief pitchers). As mentioned in my first Runs Prevented Ranking post, however, the direction of change expected for Brewers pitchers suggests that this performance may not continue overall.

What is intriguing is that when one aggregates DRA Runs Prevented by team, the major contenders in the NL Central are each due rather large corrections. The Cardinals, Brewers, and Cubs are each “off course” by more than 30 Runs Prevented, according to DRA metrics, which raises an interesting question about pitching staff construction.

While the Brewers’ main concerns are in the starting rotation, any course correction for the Cardinals suggests that the bullpen is of concern. For the Cubs, the rotation is due a course correction, but the bullpen is also the major concern for the Lakeview Nine.

The Brewers’ pitching situation is complicated by the club’s elite fielding performance. According to Baseball Prospectus Defensive Efficiency metrics, the Brewers’ flyball defense is third best in the MLB, while their groundball defense is seventh best. Perhaps most importantly, the Brewers have the most efficient defense in terms of converting line drives into outs, as well. So while DRA suggests that the Brewers starting pitchers might not be expected to be as good as their runs prevented numbers, it is worth questioning whether the strength of the staff lies in their relationship to the fielding performance of the club. In this regard, the Brewers must carefully weigh their midseason moves: while the club may like to upgrade certain positions in terms of offensive performance, an offensive upgrade at the expense of defensive performance could be devastating to the pitching staff. One must also consider the extent to which Chase Anderson and Zach Davies can adjust, or Corbin Burnes, Alec Asher, and Brandon Woodruff could contribute quality innings.

GM David Stearns has his midseason work cut out for him. The GM has already proven his ability to design and construct a systemic ballclub that works almost as an ecosystem might, translated into baseball performance. This systemic design for the club should impact midseason moves. Perhaps this Brewers squad is not one that requires an elite, impact trade, but rather more marginal moves to continually improve the margins of the club. After all, with a club that is driven by defensive efficiency and bullpen, the Brewers are already a sufficiently marginal club to begin with: what would the 2018 Brewers look like if they lose their balance at the margins of the roster?

Photo Credit: Benny Sieu, USA Today Sports Images

Explanation: Exploring Runs Prevented

Following a new format for my articles (where possible), the tables will be presented first for those who do not wish to read about the guts.

Table One: 2018 Runs Prevented by MLB, AL / NL, cFIP, and DRA; Ranked by Current AL / NL Runs Prevented

If you cite this table, please link this article and cite Baseball Prospectus and Baseball Reference.

At the team level, Runs Prevented basically expresses the extent to which a club’s pitching staff is better or worse than the league average adjusted for their park factor. Thus, it scales team pitching production to the environment faced by pitchers (both in terms of overall league, and in terms of park). Yet, this is only one way to present the stat; strength of schedule could be included, and different park factors could also be used. I happen to prefer the multi-year factor published on Baseball Reference, but that’s not to say that other metrics are not valid for other presentations of this statistic.

Table Two: DRA Correction of 2018 Runs Prevented for 162 Game Performance

If you cite this table, please link this article and cite Baseball Prospectus and Baseball Reference.

To account for these types of variances, in recent years I have periodically scaled Runs Prevented to Deserved Run Average (DRA) and contextual Fielding Independent Pitching (cFIP) stats. The table above demonstrates 162-game Runs Allowed and “DRA Allowed,” along with an estimate using DRA to correct Runs Prevented. The benefit of using these stats to publish Runs Prevented metrics is that one can attempt to use two predictive metrics to assess teamwide performance. This essentially could help to scale expectations about whether a club’s Runs Prevented performance is sustainable; for example, as Table One showed, the Brewers’ exceptional pitching staff, a top five team by runs prevented, is basically on pace to be an average club over 162 games when assessed by both cFIP and DRA factors. So while there are reasons to think the club could sustain its performance in terms of winning (the bullpen is one of the very best in the league at 3.22 DRA), overall one might expect the club to descend back to an average Runs Prevented performance. (Should this team continue to contend for the playoffs, they could be one particularly strange playoff team, basically driven solely by elite fielding and elite bullpen performances). (Yes, the Brewers fielding performance is very, very good.)

Table Three: Variance of 162 Game Extrapolation for 2018 Runs Prevented

This is not necessarily a knock on the Brewers, however. As the table above shows, extrapolating runs prevented figures over a 162 game demonstrates remarkable variance. There is really a statistical sense in which the baseball could land any which way, meaning that an average pitching staff could be expected to land within a wide range of outcomes the vast majority of seasons. The variance figures above are not necessarily foreign, nor are they solely due to extrapolation (even if extrapolation contributes some of the variance here); in 2017 NL, the average NL club of 0 Runs Prevented demonstrated Standard Deviation of +/- 100 runs, while the average AL club of 1 Run Prevented demonstrated Standard Deviation of +/- 91 runs. (Hence, aces do not exist.) Internal to their own range of MLB, league, cFIP, and DRA Runs Prevented extrapolations over 162 games, each team does not fare much better, with a typical variance of +/- 56 runs. This range should be intuitive when one considers a club like Milwaukee, where the club could indeed finish 124 runs better than average at their current pace, or decline to 2 runs below average at a harsher DRA pace.

If the Brewers pitching follows their DRA correction course, the offensive troubles of the club will be amplified over the course of the remaining season. Thankfully, the thawed out bats in May are producing runs at a generally average rate, meaning that the club could have a completely different look by the end of the season. Milwaukee’s likely range of Run Differentials is quite well defined even after only 44 games, which places the club in an intriguing position: while the bats provide rather obvious spots for improvement, depending on how the front office views the underlying pitching performances, the pitching staff could be a site for roster improvement as well.

Photo Credit: Jennifer Stewart, USA Today Sports Images

References:

Baseball Prospectus. Team Pitching – Standard. CSV retrieved May 17, 2018.
Baseball Reference. Team Standard Pitching [MLB, NL, AL]. CSV Retrieved May 17, 2018.
Baseball Reference. Three Year Park Factors. Retrieved from baseball-reference.com, May 17, 2018.

Stats:

MLB Runs Prevented: Based on MLB RA9 of approximately 4.45, and Three Year Park Factors (Baseball Reference). [(IP/9)*(MLB_RA9 * Park Factor)] – [Actual Team RA]

League Runs Prevented: Based on NL or AL RA9 and Three Year Park Factors. [(IP/9)*(League_RA9 * Park Factor)] – [Actual Team RA]

cFIP Runs Prevented: Based on NL or AL RA9 and Three Year Park Factors, plus each club’s cFIP according to Baseball Prospectus. [(IP/9)*(League_RA9 * Park Factor)] – [(IP/9) * (League RA9 * cFIP/100)]

DRA Runs Prevented: Based on NL or AL RA9 and Three Year Park Factors, plus each club’s DRA according to Baseball Prospectus. [(IP/9)*(League_RA9 * Park Factor)] – [(IP/9) * (DRA)]

162 Game Pace Stats: For DRA and standard RA/G, take either stat and do the following: [RA/G  * 162] or [DRA/G * 162]

DRA Correction: Building on current Runs Prevented, this stat estimates what a club’s final Runs Prevented would be if the remaining games follow DRA. [Current Runs Prevented] + [ (162 Game DRA Pace) * (Percentage of Remaining Games)]