What to expect from Deolis Guerra

The first signing by the Milwaukee Brewers this offseason was, at a glance, a bit of a head-scratcher. Last winter, David Stearns and company signed Deolis Guerra to a minor league contract. He was called up in July and made just one appearance for the big league team before getting designated for assignment and outrighted back to San Antonio. He spent the rest of the season in Triple-A and opted to become a minor league free agent on September 30th. Guerra lasted only three weeks on the open market before re-signing with the Brewers on October 18th, but this time on a major league contract.

Slingin’ Stearns was obviously quite keen on bringing Deolis back into the fold, and apparently the competition for his services was fierce enough that the executive felt compelled to guarantee Guerra a spot on the 40-man roster. The right-hander turns 31 next April, is the owner of a modest 4.52 ERA across 95.2 innings in parts of four MLB seasons, and he is out of minor league options. So, what gives?

It’s no secret that Guerra’s lone outing for the Milwaukee Nine this season was a calamity. He took over the in the ninth inning of a game against the Pirates that the Brewers were leading 6-1 and retired only two batters while allowing four base hits (including a homer) and four earned runs. Milwaukee eventually won the game 7-6 in extra innings, but Guerra was DFA’d and exiled back to the minor leagues the following day.

When he was pitching for the San Antonio Missions this season, though, Guerra’s work on the mound was arguably the finest of his career. He was tabbed in 45 games out of the bullpen and worked more than one inning in 26 of them, piling up 66.2 frames in total. Along the way he posted a 1.89 earned run average, punched out 88 batters for career-best of a 34.4% strikeout rate and 11.9 K/9, and walked only 16 (2.2 BB/9). Batters hit merely .181 against him, adding up to a sterling 0.885 WHIP.

Deserved Run Average, considered to be the preeminent publicly available run estimator, suggests that the righty’s actual performance on the mound was even more marvelous than his already superb ERA. Guerra’s 1.15 DRA was third-lowest among pitchers at the Triple-A level with at least 60 innings pitched, and his DRA- of 23 translates to a whopping 77% better than the average hurler at the highest level of the minors in 2019.

Guerra’s most substantial stint in the big leagues came during the 2016 season with Anaheim, but he has become a different pitcher on the mound since then. He came up as predominantly a fastball/changeup/curveball pitcher, but he didn’t miss many bats as a prospect or during his early work in the majors. Towards the end of 2016, however, Deolis adopted a slider into his repertoire, slowly phasing out his curveball in favor of the new offering. The pitch was part of his arsenal on a more full-time basis by the start of the next season, and since then, Guerra has seen his ability to induce swings-and-misses — and prevent runs — ascend to new levels.

Guerra punched out 41 batters in 41.0 innings at Triple-A in 2017 while posting a 1.98 ERA, but his work at the MLB level for the Angels that season demonstrated that he was still searching for consistent command of his new weapon. Typically stingy with walks, Deolis doled out a dozen of them in 25.0 frames with the Angels while logging a 4.68 ERA. But he also generated swinging strikes at a 14.9% rate, more than a five percent boost from his work at the game’s highest level the previous year. The following season in Triple-A with the Rangers, Guerra whiffed 71 batters in 59.1 innings and slashed his base on balls rate back down to 2.4 per nine. That preceded his superlative performance in relief for San Antonio in 2019.

Never much of a flamethrower, Guerra nonetheless posted the firmest average fastball velocity of his career at 92.2 MPH during his small MLB sample in 2019. He is able to generate an above-average amount of spin with the pitch, too, ranking in the 80th percentile among those qualified this past season. Guerra still relies heavily on his changeup as his primary off-speed offering, typically throwing it as often as, if not more than his heater. After that is when he mixes in his slider, usually between 10-20% of the time and generally against right-handed hitters to neutralize the reverse-platoon split that has plagued him at times throughout his career. Utilizing that cache of oblations, Deolis impelled swinging-strikes at greater than a 20% frequency in Triple-A this season.

Guerra hasn’t received much of an extended opportunity to show what he can do against the best hitters in the world since he overhauled his arsenal, but it appears that he will finally get that chance it 2020. It is no small deal to ink a minor league free agent on a big league pact (especially one who can simply opt to become a free agent if he is outrighted again), meaning that Guerra’s spot on the 40-man is almost surely safe during the upcoming offseason and that he ought to have a leg up on the competition when it comes to winning a spot in the bullpen next spring. A former top prospect (in the Johan Santana trade) turned Rule 5 draft pick turned veteran journeyman, Deolis Guerra may finally be on the verge of his long-awaited big league breakout.

Statistics courtesy of Baseball-Reference, Fangraphs, Baseball Prospectus, and Baseball Savant