Last season, the Pittsburgh Pirates’ starting rotation ranked 21st in fWAR (8.2). Their ERA of 5.40 was the fifth-highest among all 30 teams.
Simply put, they weren’t good. If we have a season in 2020, the starting rotation will most likely consist of Chris Archer, Joe Musgrove, Trevor Williams, Mitch Keller, and Steven Brault.
There is a pathway to seeing these guys improve. It may even be an easy fix.
Throw less fastballs
Last season, under the umbrella of Ray Searage, the Pirates threw more fastballs than any other club in baseball. The staff as a whole led the league in fastball rate at 59.3 percent. The starting rotation ranked second among all teams at 57.4 percent.
For some teams, a heavy dose of fastballs does work. The starting rotations of the Rangers, Athletics, and Braves ranked 10th, 11th, and 12th respectively in fWAR in 2019 while throwing more fastballs than almost every other team in baseball. For the Pirates though, more fastballs led to less success.
Take Musgrove for example. In 2019, his three worst pitches were his four-seam fastball (opponents registered a 138 wRC+ against it), sinker (147 wRC+), and cutter (125 wRC+). One of those three pitches were thrown nearly 60 percent of the time. His best pitch by far, the slider (36 wRC+), was thrown nearly a quarter of the time. His next best pitch, the curveball (68 wRC+), was thrown nine percent of the time.
Archer was the same way. His slider (92 wRC+) and changeup (90 wRC+) were his best pitches. They were thrown at a rate of 35.6 and 12 percent respectively. His four-seam fastball (118 wRC+) was thrown more than any other pitch.
During his cup of coffee in the bigs last year, Keller’s four-seam fastball got destroyed (217 wRC+) yet he threw that pitch 60.1 percent of the time. On the other hand, his curveball (17 wRC+) and slider (45 wRC+) were excellent. They were thrown just 35.4 percent of the time in total.
With the exception of Williams, every Pirate starter’s worst pitch in 2019 was some variation of the fastball. Yet they all relied on that pitch more than half of the time.
With Searage’s one-size-fits-all sinker ball philosophy gone, perhaps there is nowhere to go but up for the Pirates’ pitching staff. Oscar Marin is the new pitching coach. Last season, he was the Rangers’ pitching coach, who I noted earlier, threw a ton of fastballs in 2019.
For the Pirates sake though, it would be best if Marin left the fastball heavy philosophy in Texas.