Guerra came to the Brewers off of waivers after a winding journey to his Major League debut in 2015 as a member of the White Sox. The rookie began the 2016 season in AAA, where he performed admirably in the unfriendly Pacific Coast League.
After five starts and a 25:11 K:BB ratio with the AAA Sky Sox, Guerra was called up to Milwaukee on May 5th. His first pair of starts were decent performances, but he settled in shortly after that.
In total, Guerra made just 20 starts for the Crew in 2016, but his performance was still a historic one for the franchise.
He finished the year with the lowest ERA (2.81) by a Brewer with at least 100 innings pitched since C.C. Sabathia‘s remarkable year in 2008.
It was also the the lowest ERA by a Brewers rookie (min. 100 IP) and the lowest batting average allowed (.211) since Cal Eldred in 1992.
He also finished second all-time among Brewers rookie pitchers (min. 100 IP) with his 2.81 ERA, again to Eldred (1.79 ERA).
Guerra handily led the Brewers’ pitching staff in Baseball Reference’s measure of player value, with a 4.0 rWAR. It was the highest rWAR by a Brewers pitcher since Sabathia in 2008.
He also had the lowest ERA in the Majors by a rookie starter with at least 100 innings pitched. Overall, Guerra held opponents to a sterling .633 OPS.
Historically, rookie pitchers with Guerra’s success over 30 years old are exceptionally rare, as FanGraphs covered last month.
For his part, fellow rookie Zach Davies led the Brewers’ pitching staff in fWAR (2.8) and WARP (3.3), thanks to solid numbers across more innings than Guerra. In fact, according to FanGraphs, metric, fWAR, Davies had the Brewers highest value for a starter since 2012.
Davies finished the year with 163 1/3 innings pitched and a solid 3.97 ERA (3.89 FIP). He also struck out batters at the same rate as Guerra (7.4 batters per 9 innings) while issuing walks roughly two-thirds as often.
In 2016, Tyler Thornburg had one of the finest years by a Milwaukee Brewers’ reliever in recent history. Though he only took over as closer near season’s end, Thornburg was dominant the entire year.
He struck out 12.09 batters per 9 innings, third-highest in Brewers history for a pitcher with at least 50 innings pitched. Thornburg also earned the highest fWAR (2.0) for a Brewers reliever since Francisco Cordero in 2007, and the highest rWAR (2.4) since Derrick Turnbow in 2005.
He also had the Brewers’ the lowest batting average allowed among relievers (.161) since Matt Wise in 2005.
Jeremy Jeffress had a nearly flawless season with the Brewers. He saved 27 games with just one blown save in 44 2/3 innings. Before his trade to the Rangers, Jeffress posted a 2.22 ERA (3.17 FIP) as the Brewers’ closer.
Jeffress was an extreme groundball pitcher in his final stint with the Crew, inducing grounders on 57.7% of balls in play. The average for all pitchers in 2016 was 44.7%. Additionally, just 20% of balls put in play against Jeffress were quantified as hard hit. The average hard hit% among relievers in 2016 was north of 30%.