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Thursday, December 8, 2022

Past, Present, Future: The Pirates’ Rotation Saw Changes, and Looks Promising Going Forward

This is the start of a season recap feature that will run this month, looking at each position on the Pirates with a focus on the recent past (2018 season), the present (what the 2019 team looks like) and the future (years beyond 2019).

The Pirates’ rotation went through a transformation this year, both in terms of personnel and strategy. Prior to the season, the team traded Gerrit Cole to the Astros. That trade quickly looked poor, as Cole turned things around with the Astros, thanks in part to a new approach that saw him throwing his fastball less often, and his breaking stuff more often.

The Pirates had been throwing their fastball over 60% of the time and using the breaking stuff about 20% of the time up to that point with almost all of their pitchers. That was an approach that used to work, but which was no longer leading to success the last few years.

Maybe it was coincidence, or maybe it was intentional, but the Pirates saw a strategy change when Joe Musgrove — who was acquired from the Astros in the Cole trade — was activated from the disabled list in late May. Musgrove continued pitching in the same way he pitched with the Astros, throwing more breaking stuff and fewer fastballs. When he returned, you started seeing a few Pirates starters adopting the same approach.

The most notable was Jameson Taillon.

Taillon introduced a new slider in his May 22nd start, throwing the pitch about 5% of the time. His very next start saw an adjustment, throwing the pitch 35% of the time, and throwing his fastballs 55% of the time, which was well below his previous usage.

Up until that point, Taillon had a 4.56 ERA and a 3.95 xFIP. After the change in approach, he had a 2.71 ERA and a 3.45 xFIP the rest of the year. The new slider was a dominant out pitch, but it also had a positive impact on his sinker, leading to better results from that pitch, likely due to the similar initial look that a sinker and slider can have.

The Pirates had their ace. But then they added to Taillon by trading for Chris Archer at the deadline, giving them two top of the rotation type guys.

Archer didn’t start out looking that way when he arrived in Pittsburgh. His first month was rough, with a 6.45 ERA and a 3.98 xFIP. He started looking like Chris Archer again in September, with a 2.70 ERA and a 3.19 xFIP. His pitches were seeing better results, and he cited trust in Francisco Cervelli’s game calling as a big factor for the improved results.

Another big story this year in the rotation was Trevor Williams. He posted a 3.11 ERA and a 4.54 xFIP, which does raise some questions about whether his success can be carried over in the future. That success wasn’t consistent as the year progressed, but he did finish on a strong note.

Williams started off strong, putting up a 2.29 ERA and a 5.13 xFIP in his first month of the season. He did have a 3.67 FIP, with the key difference being his low HR/FB rate, which was around 10% for his career, but just 2.6% during this stretch.

That changed from May until the start of July, as Williams started giving up home runs again, only this time at a rate higher than normal. He had a 5.98 ERA and a 4.55 xFIP, with his FIP being 4.98. This time the xFIP was lower because he was actually unlucky with a 15.5% HR/FB rate.

Then, over the final three months, Williams repeated his first month success in a big way, posting a 1.29 ERA, a 3.10 FIP, and a 4.27 xFIP. He had a 3.8% HR/FB rate during that stretch, while also showing improvements with his strikeouts and walks from the start of the year.

Joe Musgrove and Ivan Nova both put up numbers close to league average. Musgrove had a 4.06 ERA and a 3.92 xFIP, while Nova had a 4.19 ERA and a 4.28 xFIP. Chad Kuhl had a 4.55 ERA and a 4.33 xFIP. He also made a switch similar to Taillon at the end of May, but went down with an injury at the end of June and needed Tommy John surgery.

Nick Kingham, Steven Brault, and Clay Holmes were used as depth starters, but none of the three posted an ERA lower than 5.00.

The Prospects

The Pirates traded some of their pitching depth this year, sending out Tyler Glasnow, Shane Baz, and Taylor Hearn at the deadline in the deals for Chris Archer and Keone Kela. They managed to keep their best prospect, Mitch Keller, who should join the big league rotation in the next year.

While the Pirates were seeing their big league pitchers learning to throw the breaking stuff more often, and the fastball less often, Keller was doing the same in the minors. A lot of his focus was on throwing the curveball and changeup more often, and learning that new approach to pitching. Keller has a curveball that is a plus offering, along with an improved changeup that projects to be an average MLB pitch. His fastball works in the mid-to-upper 90s and typically has above-average or plus control. He’s got the chance to be a top of the rotation guy in the majors, and with the Pirates changing their approach to pitching, there is less concern that they would waste that upside.

The Pirates have a lot of depth options in the upper levels of the minors who profile as back of the rotation starters at best. Indianapolis had Holmes and Kingham, who didn’t have good seasons in the majors this year, but have more talent than their initial results. Of the other options, JT Brubaker is the most intriguing, due to his continued upper 90s fastball this year, along with improvements shown from his new cutter.

Holmes, Kingham, and Brubaker should make up some of the depth options for next year, with Kingham likely to start off in the MLB bullpen due to being out of options. Eduardo Vera and Dario Agrazal are two guys from Altoona who could have a shot at the majors next year.

As far as potential top of the rotation talent, or even middle of the rotation guys, the Pirates are pretty bare right now behind Keller. That’s in part because of their trade of Shane Baz. However, they have a lot of promising guys in the lower levels who were taken out of the prep ranks in the last three drafts. There are so many options that the Pirates have a good shot of one of them emerging as the next Keller and becoming more than just a back of the rotation guy.

The good news is that the MLB rotation is set for a few years, which leaves the system time to develop some future starters.

The Future

The rotation in 2019 will be led by Jameson Taillon and Chris Archer. That’s a solid 1-2 combo if you believe that Taillon’s change over the final four months was lasting, and if you believe that Archer’s August was just a fluke.

The Pirates also have Musgrove and Nova, who are capable of putting up average numbers in the rotation, and possibly slightly above-average numbers.

The wild card here is Trevor Williams. I don’t think he will repeat his surface numbers of a 3.11 ERA going forward. He has out-performed his advanced metrics in the past, but never at this rate. He had a 4.49 xFIP last year, but a 4.07 ERA. This year saw a 4.51 xFIP and a much better ERA. That was due to a much lower BABIP (.291 to .261), a higher strand rate (71.4% to 76.6%), and a lower HR/FB rate (9.9% to 8.0%).

It takes 2000 balls in play for a BABIP number to stabilize. It takes 400 fly balls for a HR/FB rate to stabilize. Williams has just over 1,000 balls in play in his MLB career, and 342 fly balls. In that time he has a .279 BABIP and a 9.6% HR/FB rate.

Because of this, we don’t know for sure whether he can post numbers better than the typical league average ranges of .300 and 10%, respectively. It’s possible that he could be a guy that puts up a BABIP below .300. It seems less possible that he could be a guy who puts up a HR/FB rate well below 10%, since he’s close to that number already, and closer to a stabilization point with his fly ball totals.

In short, I’d expect Williams to regress next year. The big question is how much will he regress? At the least, I think he can be another guy who can put up league average numbers. I’ve mentioned that a few times, and I should note that the league average this year was a 4.15 ERA. Having three pitchers who can do this, along with that strong 1-2 combo from Taillon and Archer would be a good rotation.

If Williams can improve on those numbers, and show that he can continue exceeding his xFIP results, then that’s just an added bonus for the Pirates.

I’d expect Mitch Keller to join the rotation next year, which could provide another boost. Typically you don’t want to rely on prospects to come up and have success right away, but Keller has a profile similar to Taillon and Cole, who both came up and immediately had success.

Going forward, the Pirates have Taillon under control through the 2022 season, Archer through 2021, and Musgrove and Williams also through 2022. The addition of Keller would have their rotation set for the next few years, with that 2020-2021 group looking very promising led by Taillon, Archer, and hopefully a quickly established Keller.

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Tim started Pirates Prospects in 2009 from his home in Virginia, which was 40 minutes from where Pedro Alvarez made his pro debut in Lynchburg. That year, the Lynchburg Hillcats won the Carolina League championship, and Pirates Prospects was born from Tim's reporting along the way. The site has grown over the years to include many more writers, and Tim has gone on to become a credentialed MLB reporter, producing Pirates Prospects each year, and will publish his 11th Prospect Guide this offseason. He has also served as the Pittsburgh Pirates correspondent for Baseball America since 2019. Behind the scenes, Tim is an avid music lover, and most of the money he gets paid to run this site goes to vinyl records.


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