2023 Tigers player previews: Spencer Turnbull is the starting rotation’s ace in the hole

Mar 20, 2023 - 1:00 PM

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Other than Miguel Cabrera himself, no player in the Detroit Tigers’ organization is longer tenured than the man known as Red Bull. Spencer Turnbull was drafted out of Alabama way back in 2014 with their second round selection. For four years he worked his way through the farm system dealing with minor injuries and bouts of wildness. The stuff was always excellent, but every time he started to put it together another minor injury set him back again.

Things finally started to come together for Turnbull in 2019 when he reached the majors for the first time late in the season. Steady improvement in 2020 led to a real breakout in 2021, punctuated by a no-hitter against the Seattle Mariners on May 18. But once again, just as Turnbull unlocked a new level, an injury knocked him back down.

The return from UCL reconstruction will have a lot to do with how he’ll perform and that’s tricky to predict, but his stuff looks undiminished this spring. He’s had a good 20 months to recover and everything looks very positive right now. Still, Turnbull has never been terribly durable, and it remains to be seen how much of a workload he can handle and how long it will take him to fully recapture the improved command he had in 2021.

Of all the high draft picks the Tigers have spent on pitching in the eight years since Turnbull was drafted, none of the top picks have developed a better fastball-slider combination than he possesses. Really, only Tarik Skubal has come close. Turnbull has uniquely dominant stuff when he’s right. It’s about staying healthy and recapturing the command he showed in 2021. Based on his spring outings, things are coming together very well at this stage of the comeback. The Tigers rotation looks far better in both 2023 and 2024 if Turnbull can finally earn a reprieve from the injuries.

His fastball velocity has been good in his spring outings, sitting around 94 mph, while his slider has come around more recently. A few hangers have been hit hard, but that’s to be expected as he works to get his command all the way back. With nine punchouts in 7 ¹⁄₃ innings and one walk allowed, things are progressing nicely despite a couple of shaky innings along the way.

As long as he’s healthy, it’s hard not to be optimistic about Spencer Turnbull. He is a bit of a freakshow of a pitcher in terms of stuff. Few starters in baseball possess a more distinctive and dominating set of fastballs. He’s always had a little trouble commanding the whole package at once, and that was the big step we saw him make in 2021. But the compendium of small injuries over the years, culminating in Tommy John surgery, just makes it hard to bet that the 30-year-old veteran will ever post a couple of 180 inning seasons back-to-back, for example. You take what you can get until proven otherwise.

Spencer Turnbull’s unique fastball combination

The platform Turnbull is built on starts with his distinctive mix of fastball types. He leads with a fourseam fastball that gets plenty of whiffs and is rarely barrelled up. Turnbull has allowed just two home runs against his fourseam fastball in his last 106 ²⁄₃ innings and hitters slugged a miserable .328 against it in 2021.

And if he wants another wrinkle, Turnbull can turn the fourseamer into a true cut fastball at 92-93 mph. His normal fourseamer is already a strange, straight fourseamer that is extremely deceiving to hitters. It’s spin profile to hitters looks like a normal riding fourseamer with modest tail, but instead it straightens out and drops due to the spin deviation and seam effects. And as much of an interesting unicorn as the fourseamer is, he can also bend a cutter even more to his gloveside at nearly the same velocity. You just don’t face a guy like this too often, and while his extension is just average, prime Turnbull can pretty comfortably sit at 95 mph and reach back for 97-98 in a jam.

The lesser thrown sinker has nasty tailing movement and was also really tough on hitters in 2021, producing some highlight reel swerve, and cracking more than a few bats along the way. The average launch angle against the sinker in 2021 was negative three degrees. Hitters could do little but beat it into the ground.

For those familiar with Statcast movement and spin data, look at the deviations between spin-based and observed movement. This is a real freakshow in terms of stuff. To put this in simple Statcast chart terms. Look how red all his pitches are in the movement charts, and how incredibly blue his fourseamer is by comparison.

Underlying their actual movement profiles is the fact that the different fastball types and the slider Turnbull throws take advantage of seam effects, moving contrary to how the spin on the ball tells hitters they should move. Not only does he get good movement, there is plenty of deception involved that makes it very hard to barrel any of his fastball types. The result, and this feature of his game has held up at every level he’s pitched at, is that Turnbull doesn’t give up many home runs. Even when he’s battling his control and not racking up that many strikeouts, it’s just extremely difficult to hit anything hard in the air against him.

This article is two years old and already a bit out of date on one or two points, but if you’re not familiar with the seam-shifted wake concept, it should give you a decent grasp of the idea.

It’s a real oddity to have two fastballs that are that individually strong, and then to still have a sneaky cut fastball for special occasions. Lance Lynn comes to mind as one of the few real comps available who have three tough fastball types to deploy as a starter. This is really difficult look for right-handed hitters in particular. And then Turnbull also packs a good slider as well. Truth be told, his changeup and his curveball both profile as above average pitches too, he just doesn’t use them much.

The slider averages 85 mph and moves pretty viciously down and away from right-handers. Turnbull had an excellent 37.6 percent whiff rate against it in 2021, and like the sinker it is very rarely hit hard in the air. Even when it’s not terribly sharp he can throw it for strikes down in the zone and get plenty of routine ground balls. The slider had an average launch angle of just seven degrees in 2021. As with the fastballs, good luck trying to barrel anything up.

When he started commanding the slider more effectively during the shortened 2020 season, the whole repertoire really came together for him. The whiffs started piling up and he was able to carry that over into 2021 with even greater success. That development had him looking like a potential ace before the elbow finally gave out.

So, Spencer Turnbull is absolutely filthy. That’s the simple takeaway here. Finding a set of pitch profiles like this in one pitcher is rare. He’s always had fantastic stuff. Even his curveball and changeup have a ton of movement. He just doesn’t need them as more than a change of pace. Staying healthy and commanding the whole package at the same time has always been the problem.

If Turnbull throws strikes and mixes up his stuff effectively? He’ll have a good comeback season. But if he can get all the way back to the level of precision and game planning he and Chris Fetter found in their first season working together, Turnbull is going to get more punchouts and dominate once again. That may take some time, but things are tracking in the right direction this spring. The Tigers rotation could be a good deal better than people expect if Turnbull can get all the way back to his best.

We’ll leave you with a reminder of what Spencer Turnbull’s best really looks like.