Junior Guerra looks like he’s back

The Milwaukee Brewers are reeling a bit after getting swept in a four-game series over the weekend at Wrigley Field, but one can hardly place any blame upon the pitching. The hurlers allowed only nine runs during the series, and that was with little aid from the defense. The Brewers’ offense has come and gone so far during the 2018 season, but the one constant has been the excellent production from the team’s arms. Entering today, the club owned MLB’s third-best ERA at 3.14, was tied for eighth-best in the league by FIP- (94) and 10th-best by DRA- (91).

The starting rotation was perceived as a weak link entering the season by pundits both locally and nationally, but at this point, Milwaukee’s initial out-getters have put together a 3.62 ERA that ranks #8 in baseball. Chase Anderson, Zach Davies, and Jhoulys Chacin have each performed more or less as expected, but the leader of the staff has been someone who didn’t even make the Opening Day roster:

Major League Baseball ERA leader (min. 20 IP) Junior Guerra.

Before Spring Training, I profiled the #2016BrewersAce as a possible bounceback candidate after digging into his statistical and scouting performance during Venezuelan winter ball and advised readers to be cautiously optimistic about his outlook for 2018. Despite a strong showing during Cactus League play, the 33-year-old began the year in the minors but didn’t stay there long. He made the Opening Day start for the AAA Colorado Springs Sky Sox, allowing just two hits and one run over 5.2 innings. When Milwaukee needed a starter on April 11th against St. Louis, it was Guerra who got the call. He has proceeded to exceed even the most sanguine of expectations.

Now in four starts since being recalled, Junior has tossed an even 22.0 frames while yielding only two earned runs for a sparkling 0.82 ERA. He’s allowed just 13 hits and eight walks for a sub-1.00 WHIP, while setting down 21 opposing hitters on strikes. His most recent start against the Cubs on Saturday may have been his finest work yet, as the righty worked 6.0 innings and allowed just one run, which only came across after three players converged on and failed to catch a routine fly ball to shallow center field. That “double” was one of the three hits Guerra allowed in the outing, with another one being a pop-up in the infield that dropped between Hernan Perez and Orlando Arcia and was scored a single. Junior walked two batters and whiffed six, but was the tough-luck loser when the offense failed to plate any runs in support of him.

Guerra obviously struggled mightily last season, dealing with both a loss of velocity and the strike zone on his way to a 5.12 ERA, 129 DRA-, and 5.5 BB/9. But this season, he’s been Milwaukee’s best starter by ERA, FIP, and DRA, and appears to have made some real improvements that are driving his stellar performance. First and foremost, his mechanics and release point appear to be back in order.

After taking the 2016-17 winter off for the first time in eight years, Guerra’s vertical release point rose by some one-to-two inches on each of his pitches across the board during his lost 2017 campaign. It seems reasonable to conclude that the long winter layoff threw Guerra out of his typical routine, and while the club’s intentions may have been noble after he logged nearly 150 innings in 2016, holding him out of the LVBP may have actually hindered Junior quite a bit last season. This past offseason Guerra was allowed to work a full winter ball slate and tossed 77.0 innings between the regular season and playoffs, and perhaps not coincidentally has looked very sharp out of the gates in the 2018 regular season. He’s getting much better drive through his delivery, and early on he appears to have relocated his proper release point:

The chart above illustrates pretty clearly the marked increase in Guerra’s vertical release points from 2016-17, but it’s also not tough to see the mechanical corrections that appear to have taken place so far in 2018. According to the data, his release points have each fallen right back in line with where they were in 2016. Visually, here are three telling images of Guerra’s release point, in order from 2016-to-2017-to-2018:

With his delivery back under control, Guerra has been able to hit the strike zone with much more consistency so far in 2018. Two years ago, Junior was over the plate with 43.8% of his pitches, but that total fell to just 38.9% in 2017, one of the lowest percentages in the majors. This season, Guerra has found the strike zone with 45.9% of his offerings, including what would be a career-best 62.5% first-pitch strike rate. The Baseball Prospectus metric ‘Called Strike Probability’ serves as a measure of a given pitchers’ control of the strike zone; after posting CSProb totals of 45.49% and 41.44% in 2016 and 2017, Guerra is all the way up to a 49.46% Called Strike Probability in 2018.

Guerra’s fastball velocity has also noticeably rebounded; after averaging 92.4 MPH last season (and struggling to reach 90 MPH at times), his typical heater has improved to 93.4 MPH and he’s already touched 96 MPH in 2018. Opponents torched Guerra’s four-seamer for a .288 batting average and .591 slugging percentage in 2017, but this season he’s turned the offering into a weapon:

So far in 2018, Guerra has added nearly 150-175 RPM of spin rate to his fastball over his previous marks from 2016 and 2017. That’s helped him go from a rank in the bottom 30% in the league in terms of highest fastball spin rate to within baseball’s top 36% of pitchers. In fact, no pitcher in baseball has added more spin to their four-seam fastball this season than the 174 RPM increase Guerra's produced. He’s also shifted how he’s using his four-seam compared to last season, getting the ball out of the middle of the zone and focusing more on the lower, glove-side quadrant of the strike zone as well as attacking the upper half of the zone more frequently. He’s using the pitch more often as a put-away offering with two strikes, especially to left-handed hitters. Batters have hit only .250 against Guerra’s four-seamer this season with just a .344 SLG, and that’s with a .348 BABIP (his four-seam BABIPs were .264 and .265 in the two previous seasons). The boost in velo and spin rate has helped Junior experience a three-point increase in whiff rate with the pitch, and he’s notched nine strikeouts with his heater to this point.

Junior’s signature split-finger (wSF of +2.4) remains on point, as usual - batters have hit .000 against it so far this season with six strikeouts - and it has been even more dangerous with the improvements that he’s shown with his fastball and slider (wSL of +2.0). Batters are hitting only .169 against Guerra and he has yet to give up a home run after coughing them up at a rate of 2.3 HR/9 last season. Guerra has yielded hard contact at a career-low rate of 30.9% to this point, which is three points below the league average. That, combined with a 39.6% fly ball rate and incredible 28.6% infield fly rate, should help alleviate some concerns regarding his low .232 batting average on balls in play, which in reality isn’t much different than his .236 BABIP in 2017 or his .249 career BABIP.

Junior Guerra isn’t going to finish the year with an earned run average below one, but right now, he’s the league leader in ERA (min 20 IP). According to both FIP- (68) and DRA- (83) he’s been a well above-average pitcher league-wide as well as the best starter for the Cream City Nine. He’s ironed out his delivery, recovered his lost velocity, and has weaponized his four-seam fastball. He’s striking out a career-best 23.9% of hitters and has shaved four-and-a-half points off his walk rate. The season is still only a month old, and time will tell if Junior Guerra will be able to sustain his much-improved production for the rest of the summer. But the arrow appears to be pointing up for #41, and perhaps we won’t be referring to the right-hander as the club’s “former” ace for much longer.

Statistics courtesy of Brooks Baseball, Fangraphs, Statcast, and Baseball Prospectus