Breaking Down the Pirates’ 2020 Rotation

The Pirates didn’t have a horrible starting rotation in 2020, but the group wasn’t good either. They combined to rank 19th in the majors in ERA, 23rd in xFIP, and 28th in WAR. The rotation showed some signs of hope for the future, while also showing some obvious holes that need to be filled before the Pirates hope to contend again.

As part of the recap to the 2020 season, and preparation for the upcoming offseason, I’ll be reviewing the Pirates each day by position. Each position will include two articles: A look back on the 2020 season, and a look ahead.

Today we’ll start off with a look back at the 2020 Pirates’ rotation. Tomorrow I will follow up with a look ahead to 2021 and beyond.

Mitch Keller

2020 Stats: 5 G, 5 GS, 21.2 IP, 2.91 ERA, 6.57 xFIP, 6.65 K/9, 7.48 BB/9, 1.66 HR/9, .104 BABIP, 93.8 LOB%, 16.0 HR/FB%, 44.2% GB

Keller’s stat line above reads very well until you get beyond the ERA. At that point, you see flashes of what is working for him, but a lot more examples of what is going wrong.

Keller’s season was shortened due to an oblique injury. He finished the year strong with 11 no-hit innings in his final two starts, but gave up ten walks in those outings, with eight walks in his final start. Keller had control problems in three of his five starts. He had a strikeout per inning average in two of his five starts. He had two starts where he gave up two home runs per game.

The September 19th start from Keller against St. Louis is what you hang your hopes on for his future. That’s the only start where Keller was truly dominant. That’s not to say his stuff wasn’t dominant in the next start, when he threw five no-hit innings, and overcame eight self-inflicted free passes with only one run allowed. The start against the Cardinals showed how Keller can be a top of the rotation pitcher, as long as he can put up results like that more consistently.

The problem is that the start against the Cardinals is on an island among Keller’s five starts. Keller had a Game Score above 50 in three of his starts. They each tell the story of a different pitcher.

September 19th: 79 Game Score, Average strikeouts, Above Average control, no homers, .000 BABIP

July 26th: 60 Game Score, Below-Average strikeouts, Below-Average control, no homers, .154 BABIP

September 25th: 55 Game Score, Below-Average strikeouts, Poor control, no homers, .000 BABIP

The trend running through each of these starts is that Keller wasn’t getting hit, and didn’t give up any homers. That tends to be a key to success for a lot of pitchers. The notable thing is that Keller was able to overcome all of these walks with a mostly pitch-to-contact approach. His average exit velocity in that eight walk game was 79.3 MPH. The MLB average for starting pitchers this year was 88.4 MPH. Keller beat that average in his final two starts.

Keller will need to eliminate the home runs from the other games. He’s a guy who can get strikeouts, but tends to post below-average numbers in that category. He can limit walks, but tends to post high numbers in that category. He’s capable of limiting hard contact and posting a low BABIP. Think of this like throwing four different dice, and hoping for 3-4 of them to hit the right numbers.

When Keller hits on all four of the above, he’s a top of the rotation guy. When he’s down to only having 2-3 of the above categories, he’s more middle of the rotation. When he’s only hitting on one category, he looks like a back of the rotation guy.

The hope is that Keller gains some consistency in some of these areas, so it’s not a gamble every start whether he’ll have issues with control, or low strikeout totals, or issues with the long ball.

Joe Musgrove

2020 Stats: 8 G, 8 GS, 39.2 IP, 3.86 ERA, 3.19 xFIP, 12.48 K/9, 3.63 BB/9, 1.13 HR/9, .318 BABIP, 77.3 LOB%, 17.2 HR/FB%, 48.4% GB

The more I dig into Joe Musgrove’s numbers, the more I think he’s the sleeper on this Pirates’ team. The Pirates will be relying on Mitch Keller to step up from being a prospect to leading the rotation. They’ll hope that Jameson Taillon returns like it’s 2018. But Joe Musgrove might be the best bet to lead this staff.

The numbers above are strong across the board, led by elite strikeout numbers. Musgrove’s K/9 ratio ranks 10th in the majors out of 165 starters with 20+ innings. What’s even more impressive is that his average exit velocity ranks fourth in the same group. The guys ahead of him are Ryan Yarbrough, Max Fried, and Jordan Montgomery, with Kenta Maeda right behind him.

This is good company for Musgrove to be in, but how much of that is sustainable? Musgrove has never come close to these strikeout numbers, and only has one season with an average exit velocity close to this one. That came in 2017 with the Astros, when he had an 86.7 MPH average exit velocity.

Musgrove made an adjustment to his pitch usage. He reduced the amount of four-seam fastballs to 39.1%, and increased the usage of his curveball up to 19.9%. His fastball isn’t a big swing and miss pitch, while the curve had a 17.2% swing and miss rate this year. The slider was at 22.1%. Musgrove also had two lesser used pitches in double-digits, with a changeup at 12.3% and a cutter at 22.5%.

Musgrove’s slider typically plays well, but the curve stood out in many ways this year. It led to a .186 OPS against, and was responsible for 13 strikeouts. The pitch led to very low swing counts when thrown in the strike zone, which means a lot of taken strikes to go with the high swinging strike rate.

The main drawback is that Musgrove doesn’t have a strong fastball to lead the way. He gets by with a reduced four-seamer, and three other pitches to pair with the slider and curve. It will be interesting to see how he adjusts the usage of his pitches next year after seeing so much success from the increased curveball usage this year.

Trevor Williams

2020 Stats: 11 G, 11 GS, 55.1 IP, 6.18 ERA, 4.94 xFIP, 7.97 K/9, 3.42 BB/9, 2.44 HR/9, .313 BABIP, 70.0 LOB%, 24.2 HR/FB%, 44.6% GB

This will probably end up being the final year for Williams with the Pirates and in the Pirates’ rotation. Out of his 11 starts this year, only three ended up with a game score of 50 or better. Two of those good starts saw him overcome control issues.

Williams doesn’t have a dominant pitch. He got by his first few years with a dominant fastball combo. His four-seam and sinker were both posting sub-.700 OPS results prior to 2019. He looked to the slider, changeup, and curveball for an out pitch, but has yet to find success with any one offering. This year the fastballs both jumped to the .975 OPS range, while the changeup was his best pitch at a .769 OPS. He threw a curveball which had a .250 OPS against. The pitch hadn’t been good in previous years, but he doubled his career usage of the offering in one season to good results. He might consider using that pitch more often going forward, pairing off his four-seam.

Williams was pitching well in 2017 and 2018. The last two years show what type of pitcher he is when the fastballs aren’t dominant. There wasn’t really a sign of those pitches coming back, which makes him a dangerous bet in 2021 in any role. Williams wouldn’t be bad to try and retain on a minor league deal to see if he can get back on track in Triple-A. He also wouldn’t be a bad candidate for a pitch overhaul, with a transition of about ten percentage points from his fastballs to his curveball.

Steven Brault

2020 Stats: 11 G, 10 GS, 42.2 IP, 3.38 ERA, 4.85 xFIP, 8.02 K/9, 4.64 BB/9, 0.42 HR/9, .243 BABIP, 73.3 LOB%, 5.9 HR/FB%, 49.1% GB

I’m not sure if I’d trust Steven Brault in the rotation for an entire season. I would like to see what he could do if given an entire season in the rotation. He basically had that this year, and was one of the better performers on the team, nailed down by two dominant starts to finish the year.

A big adjustment for Brault was that he started using his changeup a lot more often. The pitch has been his best offering of his career, and had a .269 OPS against this season. His slider had a .650 OPS against, and the four-seam fastball had a .563 OPS against, which was a big improvement. Brault’s changeup and slider both get double-digit swing and miss rates, but neither stand out as a big strikeout pitch. They’re just difficult pitches to hit.

I mentioned above how Joe Musgrove was in the top five in average exit velocity this year, putting him in a category with a lot of talented pitchers. Number six on that list, just behind Kenta Madea, was Brault. When you’re throwing four pitches with a .650 OPS or less, and you’re one of few pitchers to not have a double-digit HR/FB ratio, you’re bound to wind up high on exit velocity rankings.

The question is whether that can be sustained. Brault went from a 90.5 MPH average exit velocity last year to 85.8 this year. He also made significant adjustments to his pitch usage, dropping his fastball by almost 15 percentage points, and increasing the changeup by over ten percentage points. Was Brault benefitting from pitch usage, and increasing the focus around his best pitch?

Ultimately, I think Brault should have an inside track for a rotation spot next year, aiming to see whether his stuff can be this dominant over a full season, and whether his drop in exit velocity is legit.

JT Brubaker

2020 Stats: 11 G, 9 GS, 47.1 IP, 4.94 ERA, 4.14 xFIP, 9.13 K/9, 3.23 BB/9, 1.14 HR/9, .321 BABIP, 68.8 LOB%, 14.3 HR/FB%, 46.7% GB

There’s a lot to like about Brubaker’s rookie campaign in the Pirates’ rotation. Four of his nine starts were poor, but Brubaker had three slightly above average starts, and two gems. What I like about Brubaker is that he was able to get strikeouts, limit walks and home runs, and he didn’t give up a lot of hard hit balls.

Brubaker works well off a sinker/slider combo. The sinker had a .783 OPS against this year, while the slider came in at .650 with almost as much usage. A key difference with the slider is that it generates a 17.6% swinging strike rate. Brubaker’s curveball gets a 14.3% swinging strike rate, and had a .500 OPS against this year.

Brubaker is a guy who might work best as a multi-inning reliever. He had a 3.20 ERA and a 3.89 xFIP in 19.2 innings the first time through the order this year. That jumped to 7.63 ERA and a 4.88 xFIP in 15.1 innings the second time through the order.

Chad Kuhl

2020 Stats: 11 G, 9 GS, 46.1 IP, 4.27 ERA, 4.98 xFIP, 8.55 K/9, 5.44 BB/9, 1.55 HR/9, .235 BABIP, 72.5 LOB%, 19.0 HR/FB%, 42.9% GB

Chad Kuhl returned to the Pirates’ rotation from Tommy John surgery and pitched like a back of the rotation starter. There was some promise, such as his final start of the year when he threw seven shutout innings, but there was also disaster, like the start two games earlier when he gave up nine runs in 2.1 innings.

Kuhl’s slider continues to be his dominant pitch, with a 17.9% swinging strike rate and a .510 OPS against. His curveball also emerged as a strong weapon, with a .303 OPS against and a 12.9% swinging strike rate. The problem is that both of his fastballs get hit around too much. Kuhl used his sinker and slider almost the exact same amount of times. He used his curveball twice as much as his four-seam fastball. By comparison, he used his sinker more than twice as much as his slider in 2018, and used the four-seam and curveball almost equally.

The biggest thing that stuck out to me with Kuhl was his split on times through the order. He had a 3.48 ERA and a 3.92 xFIP in 20.2 innings this year the first time through the order. That went up to a 6.75 ERA and a 5.43 xFIP in 16 innings the second time through the order. The Pirates might be best using Kuhl as a once-through-the-order reliever, capable of helping on a bullpen day.

Derek Holland

2020 Stats: 12 G, 5 GS, 40.2 IP, 6.86 ERA, 4.49 xFIP, 9.96 K/9, 3.32 BB/9, 2.66 HR/9, .288 BABIP, 62.5 LOB%, 26.1 HR/FB%, 37.4% GB

Holland is a perfect example of how weak the Pirates’ rotation was in 2020. He wasn’t bad as a reliever, with better control numbers leading to a 2.99 xFIP. He was always going to get a shot in the rotation in Pittsburgh, when his career is probably best suited out of the bullpen. The injuries to the rotation led to some fun looks to the future with some of the other players on this list. Holland didn’t have a future with the Pirates, and didn’t perform well enough to land a trade return.

Cody Ponce

2020 Stats: 5 G, 3 GS, 17.0 IP, 3.18 ERA, 5.67 xFIP, 6.35 K/9, 3.18 BB/9, 2.65 HR/9, .163 BABIP, 100.0 LOB%, 20.0 HR/FB%, 35.4% GB

Ponce didn’t do bad as a depth starter who was needed in the rotation three times over the final month of the season. He probably doesn’t have much of a future in the majors as a starter, but he could make it as a reliever who can pitch multiple innings. The bread and butter for Ponce is his fastball/curveball duo. The fastball led to some control problems, but was difficult to hit. The curveball had a .343 OPS against, with a 15.9% swinging strike rate. That combo would be enough to make Ponce a very solid multi-inning reliever.

Chris Archer

2020 Stats: Did Not Play

Archer went down for the season after surgery in June for thoracic outlet syndrome. This is a difficult injury to return from, even if he is healthy to start the 2021 season. The Pirates declined his option this weekend.