Earlier this year, Jonathan Judge and the team at Baseball Prospectus introduced a new advanced pitching metric called "Deserved Run Average," or DRA. The mixed-model statistic is thoroughly explained here, but in general it attempts to break down things like fielding, opponent strength, and even temperature in an effort to determine how many runs a pitcher truly "deserved" to allow. This number is then written as a run value similar to ERA.
Over at BP, they have been kind enough to release the run tables that are a large part of what went into determining a player or a team's DRA in 2015. This allows us to take a closer look at how our beloved Brewers' pitching staff actually performed this season and what external factors helped or hurt them.
As a group, the club's collective 4.28 ERA ranked seventh worst among the 30 teams in Major League Baseball during this past season. DRA says they were even worse than that, rating the Brewers at a 4.45 mark that tied for 22nd best. Based on DRA, the staff produced only 7.80 combined Wins Above Replacement Player (WARP), sixth worst in the league. The club was led by Jimmy Nelson, who produced 2.37 WARP during his first full big league campaign. Conversely, both Kyle Lohse and Wily Peralta were Milwaukee's least valuable pitchers in 2015, producing a putrid -1.07 WARP each.
First off, we'll look at one of the few positives that helped Brewers pitchers this past season: catcher framing. The staff collectively lost 7.03 runs according to the metric Called Strikes Above Average, thanks mostly in part to Martin Maldonado's strong performance behind the plate. Maldonado ranked 17th in the league in Extra Strikes and Runs Added by Count, more than doubling Jonathan Lucroy's marks from 2015. It's worth noting that Lucroy's noted framing skills declined significantly from 2014-15. Though he did lose time to injury, the fact that he was worth 95 less Extra Strikes and 14 less Runs Added by Count should be concerning.
Unlike the positive framing performance, the rest of the defense behind the Brewers' pitching staff was basically atrocious. The hurlers gained 20.55 runs according to Fielding Runs Above Average, sixth most in the league. Ryan Braun, Scooter Gennett, and Adam Lind all ranked in the bottom 100 players according to FRAA. The defense was particularly awful behind Matt Garza, who gained 3.03 runs, and Jimmy Nelson, who gained 2.36 runs.
As a whole, the staff gained 5.27 runs based on the strength of their opponents. By this metric, the club had the fifth most difficult slate of opponents this past season. Jimmy Nelson gained the most runs (1.33) among Brewers' pitchers by consistently throwing against the most difficult lineups. Matt Garza faltered this season despite having the easiest task among the club's pitchers, losing about half a run based on opponent strength.
The Brewers had small run gains thanks to temperature (2.02) and home/away split (2.31), and a small loss due to pitching role (-1.03). However, the biggest contributing factor by far was the stadium affect. Playing half their games in Miller Park, the Brewers collectively gained 90.18 runs, third most behind only Colorado and Boston. Unlike poor fielding or bad framing, playing in a band box unfortunately is not something the Brewers will be able to improve upon any time soon.
The Brewers' pitching staff was pretty poor overall in 2015, but they certainly didn't receive much help, either. The club's total of 112.33 adjusted runs ranks second highest behind only the Colorado Rockies, thanks in large part to playing poor defense in a hitter's ballpark while facing good teams.
As the club rebuilds, it would be wise to focus on shoring up the defense behind a staff and prospect pool that leans heavily on getting ground balls. Perhaps it might also be beneficial to the pitching staff for the club to consider moving Jonathan Lucroy and installing Martin Maldonado as the everyday catcher, at least while wins and losses are of little consequence. Finally, given the club's rebuilding state and deep stable of pitching depth, we can probably expect to see a myriad of different starters used next season based on who is and isn't effective as the club attempts to identify who will make up the "starting rotation of the future."