The Pirates’ Rotation Was Not A Problem

The 2017 Pirates season was not what many fans have hoped for. The current 73-85 record, the 2nd season under .500. Certainly there were factors outside management’s control. It was impossible to foresee Jung-ho Kang’s inability to enter the country when last offseason began. I doubt anyone expected Starling Marte to serve an 80 game suspension. The issues Jameson Taillon dealt with this year are far bigger than baseball. Each season, every team has circumstances develop outside of what they expected. The Pirates have perhaps faced more of that, on the negative end, than any other team. However, as I was thinking about how to approach the offseason, I would rather focus on positives than negatives. What has gone right?

That leads me to the Pirates rotation. As it currently sits, here is how Pirates starters compare to the rest of the league (stats as of 9/27/2017).

That isn’t exactly a model of success, you say. Why should we be happy about the 12th best rotation in the league by Wins Above Replacement?

First, let’s not focus on specific ranking. We could break rotations into tiers. We have the top tier of obvious contending teams, but that grouping falls off very quickly (Indians, Diamondbacks, Dodgers, Nationals, et al). Starting around the Brewers/Cardinals, down to the Blue Jays are is where it looks like the Pirates have performed. Exact placement doesn’t matter, but no matter how you slice it, we are looking at a rotation that has performed in the upper half of the league. Why does this matter? Let’s go back to last offseason.

Coming out of last season, the Pirates used 14 different starters, with none starting more than 21 games. By most advanced metrics, they were in the bottom third of the league. Back track to the offseason, and the idea of trading for Jose Quintana was one that gained some traction in local media. No matter how you looked at it, the rotation was not set in stone. You had Gerrit Cole and Jameson Taillon, neither of whom had thrown 120 innings the previous year. Ivan Nova re-signed. Beyond that, not much appeared set.

In an age when teams need 8 or so starting pitchers due to injury attrition, there were significant questions surrounding the 2017 rotation as we entered the year. As we leave 2017, those fears should be mostly alleviated.

As of this writing, 3 Pirates starters have made 30 or more starts (Cole, Nova, Kuhl), with Williams and Taillon making 25 and 24 respectively. Additionally, Glasnow and Brault have combined for 16 starts. 7 pitchers total. ~90% of the Pirates starts have come from 5 guys. That’s quite remarkable in today’s day and age. For those of you concerned about overuse, only Cole, Nova, and Kuhl have surpassed 150 IP. Cole will likely top 200 IP by the time the season ends, but this is not a scenario where every SP is being run into the ground.

Looking a little bit closer at the 5 main SP that have been used, we can get a little bit of a better picture. Courtesy of Andrew Perpetua’s xStats:

Name	IP	TBF	AB	scFIP	FIP	xOBA	xOBA+
Ivan Nova	185	774	723	4.65	4.48	0.343	107
Gerrit Cole	197.2	827	763	3.94	4.16	0.313	97.5
Trevor Williams	144.1	619	547	4.11	4.01	0.317	98.7
Chad Kuhl	152.1	657	571	4.46	4.30	0.335	104.5
Jameson Taillon	126.2	561	500	3.64	3.55	0.312	97.4

For reference, the league average FIP and scFIP are 4.36. scFIP is FIP based off statcast metrics. To distill it a little more simply, building a pitchers FIP based off of the quality of batted balls that they allow. Similarly, xOBA is on the same scale as wOBA, with a league average of .321. xOBA+ is scaled to 100 as league average, above 100 is below average. Based on these metrics, you could make the case that Cole, Taillon, Williams, and Kuhl were above average Major League Starters. While you could arrange these 4 in different orders depending on what metrics you wanted to consider, to have 4 starters be league average or better is pretty exciting.

League AVG	123222	86.5	11.1	3.5	33.90%	14.00%	13.70%	9.40%	13.80%	15.20%
Name	Total	avg EV	Vertical	Spray	DB%	GB%	LD%	HD%	FB%	PU%
Ivan Nova	603	88.0	8.4	3.1	36.50%	13.80%	15.40%	8.80%	15.30%	10.30%
Gerrit Cole	580	85.4	10.4	6.1	33.80%	14.50%	13.30%	10.30%	13.60%	14.50%
Trevor Williams	449	85.0	8.4	2.2	37.90%	12.90%	15.60%	9.10%	12.90%	11.40%
Chad Kuhl	444	87.7	11.1	3.3	32.70%	14.40%	14.40%	9.50%	14.40%	14.60%
Jameson Taillon	392	85.3	7.6	4.6	37.20%	16.60%	14.50%	9.40%	11.20%	11.00%

Looking a little more in depth at the exit velocities on different batted ball types, this is where Trevor Williams sticks out. Of all Pirates starters, Williams allowed the lowest exit velocity on contact. Specifically, on the worst types of batted balls Line Drives (LD%) and High Drives (HD%), the batted ball authority off of Williams was below average. When the league average pitcher strikes out over 21% of batters, it’s easy to discount Williams. However, it appears the quality of contact he has induced has more than made up for his slightly below average strike out rate.

The Pirates’ season didn’t go the way many hoped. I don’t think anyone would deny that. While there are certainly ways to improve as the team moves into 2018, I wanted to take a moment to acknowledge a bright spot. The Pirates came into the year with many questions marks surrounding their pitching. Those question marks have been mostly alleviated.