2019 Player Review: Spencer Turnbull was the Tigers Rookie of the Year

Spencer Turnbull was an obvious choice for the Detroit Tigers Rookie of the Year in 2019. The process took nearly five years, but the Detroit Tigers’ second round pick in the 2014 finally put things together to produce one of the better rookie seasons in the American League.

It’s a good thing for the Tigers that he did.

There were some modest expectations for Turnbull heading in 2019. Entering his age 26 season, it was clearly time for Turnbull to sink or swim at the game’s highest level. On the other hand, few predicted that he’d emerge to help save the Tigers’ bacon when Michael Fulmer and Matt Moore went down to season ending injuries before they even got to Opening Day.

If not for Turnbull’s modest breakout campaign, and judging by the likely replacements, the Tigers would probably have posted their worst all-time season as a franchise. They would have been in danger of going down as perhaps the worst team of the modern era. Bad is bad, and 115 losses as compared to 2003’s record 119 is a truly dubious accomplishment, but no one wants to be the worst ever.

Spencer Turnbull did much more than give the Tigers some innings, however. He made 30 starts and posted a well above average 3.99 fielding independent pitching mark (FIP), with a roughly league average ERA of 4.61, accumulating 2.9 wins above replacement per FanGraphs’ FIP based WAR calculation (fWAR). Turnbull didn’t exactly burst on the scene, and lingering questions remain after another minor bout of shoulder trouble, but he was quite effective, if not efficient for the Tigers this year. With a little more experience, and perhaps a little more help from his defense, Turnbull has the potential to build on his rookie season.

What went right in 2019?

Probably the key thing to note about Turnbull’s 2019 campaign was how it built on his 2018 season. Turnbull shrugged off a little early season injury trouble that season, eventually found a new gear and was very good all summer long. Command of both his slider and curveball rounded into better form during a successful second tour of the Double-A Eastern League and by season’s end, Turnbull had impressed in his first major league cup of coffee. The metrics made it plain that his stuff would play at the highest levels as long as he was able to stay healthy and continue to refine his command.

Those command issues in particular were still prominent enough that FanGraphs had Turnbull at just 18th overall in the 2019 Tigers’ farm system preseason rankings.

What we saw in his first full season in the majors, is that Turnbull’s mix of fastballs are plenty good enough to keep major league hitters at bay. Of all pitchers who threw 140 or more innings last season, Turnbull was sixth in fastball usage at 64.3 percent. He averaged 93.8 miles per hour across all fastball types, and while hitters were able to handle the fastball to the tune of .354 weighted on base average (wOBA), they produced a miserable isolated power number (ISO) of just .128 against the hard stuff. He gave up hits, particularly against the sinker, but not homers, and in the current scoring environment that’s enough to make him a fairly valuable asset. Only the Atlanta Braves Mike Soroka, among all major league starters (minimum 200 PA), had a lower isolated power mark allowed off of fastballs.

We wrote about Turnbull’s ability to suppress home run power back in the spring, and it’s a track record that extends throughout his minor league career so we won’t rehash all the details here. Suffice it to say that Turnbull shows the ability to mix a distinct combination of fourseam fastballs with his sinker as a change of pace, and hitters can handle the sinker to a degree, but do very little against the fourseamer despite a heavy dose of fastballs overall.

Turnbull used his sinker far more than his fourseam fastball back in 2018. This year he basically flipped their usage, throwing 70 percent fourseamers and 30 percent sinkers. Instead of pounding hitters down and in with sinkers, he lived on the outer edge and pitched at the top of the zone a little more. In the process, Turnbull produced his usual heavy ratio of groundballs and lack of hard contact in air. Despite a high walk rate and a pedestrian strikeout rate, Turnbull was able to avoid taking major damage in an outing most of the time.

What went wrong in 2019?

Certainly a WHIP of 1.44 and and a nine percent walk rate aren’t good and suggest a likelihood that Turnbull will always struggle with his command. It’s also important to note that Turnbull got off to a great start, but as has been the case for him in most seasons, a nice run was followed with injury trouble. He wasn’t quite the same pitcher after that, though his second half numbers aren’t as bad as they might first appear.

Turnbull made his debut start on April 4 this year. From that point through his June 27 outing against the Texas Rangers, he tossed 84.2 innings with a 3.19 ERA with a quality 3.84 FIP to back it up. His ERA was a cringe inducing 6.53 from that point on across 60 ²⁄₃ innings of work, but his FIP, as it usually does, painted a cleared picture at 4.20. Turnbull was probably a little lucky in the first half, but hopefully the reality is contained in those FIP numbers, and we can look for a roughly 4.00 ERA type performance from him going forward.

Despite his success this year, there remains a strong possibility that this is as good as it gets. Turnbull’s slider was quite effective, particularly against right-hander hitters this year. His curveball is a useful pitch to steal a strike or as a change of pace, but he still rarely seems confident in it, while the changeup was largely confined to the shelf in 2019.

Heading into his age 27 season in 2020, there isn’t a whole lot to bank on in terms of improvement in pitch quality. If he can find a way to improve his fastball command and attack hitters more efficiently, he’ll find he already has everything he needs. But at his age, expecting a marked improvement in command is probably being greedy.

In some ways, Spencer Turnbull was a little reminiscent of a young Michael Fulmer who burst on the scene in 2016 with heavy use of an overpowering mix of fastballs that didn’t necessarily generate whiffs so much as weak contact. Fulmer’s changeup was the key secondary to unlock his game that year, and he’s struggled to recapture it since. Turnbull probably has a better breaking ball in his slider than Fulmer has ever consistently shown, but overall his fastball probably isn’t quite as dominant, mainly because he was a little less aggressive and less precise, and he hasn’t shown many quality changeups along the way.

If Turnbull could turn his curveball or changeup into a more effective third offering, there remains a little more upside. As it, one can easily argue that his .333 batting average on balls in play, and below average strand rate mean he was actually a little unlucky in 2019. Realistically, he’s probably quite close to his ceiling as a 2-3 WAR pitcher who can never give you a full season, but if so the Tigers will take that with pleasure. If the injuries persist and impact his effectiveness when he’s on the mound, a career as a late innings reliever is always a fallback plan.

What comes next?

Spencer Turnbull turned himself from an afterthought to perhaps a real part of the future this year. He’ll have a spot in the rotation held for him next spring, and will be under inexpensive team control all the way until 2025. Time will tell if the Tigers are better off trusting in the arm of a guy who just can’t quite crack the 150 innings barrier, or whether he might be better off used as a trade piece in the years to come. Turnbull still has plenty to prove, but in a season that didn’t offer many positives, he was one of the best parts of the Tigers 2019 campaign.