The Pirates’ rotation was the best part of the team in 2017. Of course, that’s a pretty low bar. It was also probably better than a lot of us remember. Pirates’ starters ranked 12th in the majors in fWAR (11.7) and 10th in xFIP (4.26). That’s especially surprising when you consider Tyler Glasnow’s “contribution,” which consumed 13 starts. These numbers would probably be enough to get a high-offense team into contention, but of course the Pirates had one of MLB’s worst offenses.
There are maybe a couple of reasons the rotation seemed, at least to me, to be worse than it really was. One is probably that some of us are still adjusting to the post-steroids offensive spike; an ERA over 4.00 isn’t necessarily bad when the NL average was 4.34. (It’d be easier for Pirate fans to adjust to the increased offense if the Pirates’ own hitters had gotten the memo.) A second reason is that, throughout the season, even after Glasnow’s departure, there were typically multiple starters in the rotation pitching badly.
All of the five primary starters had extreme ups and downs. Maybe this sort of variance is typical of most pitchers in most seasons, but it sure seemed extreme:
First 9 starts: 2.84 ERA
Next 4 starts: 12.10 ERA
Next 9 starts: 2.83 ERA (despite 7 ER in one start)
Final 11 starts: 4.80 ERA (6.13 if you exclude two starts with 15 shutout innings)
First 14 starts: 2.91 ERA
Last 17 starts: 5.44 ERA
First 11 starts: 2.72 ERA
Last 14 starts: 5.96 ERA
First 15 starts: 5.53 ERA
Last 16 starts: 3.38 ERA
First 14 starts: 4.64 ERA
Last 11 starts: 3.48 ERA
Of course, you can play other games with this. Williams, for instance, had an ERA as a starter for the entire season of 3.65 if you exclude his disastrous first start. Taillon actually finished the season well, with a 3.25 ERA in September (and six of the ten earned runs he allowed came in his one bad start out of five that month).
What obviously sticks out in all of this is that the Pirates need two or three starters to step forward. Having no starter with an ERA over 4.44 is a very good thing in a league where the average is 4.34, but having none with an ERA under 4.07 isn’t. The only two realistic candidates of the current five are Cole and Taillon. With those two, there are two numbers that stand out. One is Cole’s HR/9 of 1.37, which was nearly twice his previous career high, and two and a half times his career average coming into the season. The other was Taillon’s .352 BABIP. Not surprisingly, both had xFIPs better than their ERAs (3.81 for Cole and 3.89 for Taillon).
Of course, that’s not really what the Pirates are hoping to get from Cole and Taillon. Both failed to get the sort of results you’d think their stuff would produce, although in Taillon’s case there’s no telling what impact the cancer surgery could have. I can’t help wondering, though, whether the Pirates’ focus on sinkers and groundballs is holding back some of their pitchers. They got a lot of credit during their three good seasons for their groundball approach, but is that what really produced the results? It looks to me like their success lines up better with seasons when their pitchers were striking out more hitters (blue is the NL rank in wins, red in K/9):
This by itself doesn’t prove a whole lot, but MLB as a whole is moving away from sinkers and increasing usage of secondary pitches, which are what produce the Ks. In 2017, five of the bottom eight teams in fastball usage made the playoffs. (The Pirates ranked first.) It also provides some indication of why the team needs Glasnow to develop, and eventually Mitch Keller.