The Toronto Blue Jays signed Tanner Roark and there may be more to like about this than first thought
The Blue Jays finally got into the free agent action by signing starting pitcher Tanner Roark to a two-year, $24 million deal. On Monday, I wrote that signing a guy like Roark (or Rick Porcello, Gio Gonzalez and Ivan Nova) would not “really quench the thirst of Jays fans, justifiably so.” Based on the initial response of Blue Jays Twitter, I was right.
I’ve written a few posts on the free agent starting pitching market over the last month or so and that was the first time I had mentioned Roark. When I examined the 2019 performances of the pitchers available, his .407 xwOBACON stood out like a sore thumb, as it was much worse than the starting pitcher average (.379). None of the other pitchers I was remotely interested in examining posted a worse mark.
Now, if that bad contact quality came alongside an exceptional strikeout-to-walk rate, the overall picture might be more palatable (Madison Bumgarner‘s 2019 is a good example of this). Unfortunately, his 14.8% K-BB% was almost precisely average. As such, his overall performance metrics generally rate him as a below-average starter in 2019—he posted a 103 FIP-, a 104 xFIP- and a .343 xwOBA (against a .321 xwOBA for the average MLB SP)—save for ERA—he posted a 97 ERA-.
So, where’s the upside here? The simple upside is that he still posted his fourth-straight 2 fWAR-plus season. That puts him in a group of 12 starting pitchers who have generated at least two wins above replacement per season from 2016 to 2019. Granted, his total fWAR (10.4) is the lowest in the group, but the point is that he is consistent. Given the last few seasons of the Blue Jays’ rotation, having a guy you can count on for 30 or so starts and roughly 2 WAR isn’t nothing.
The more unexpected upside requires splitting his 2019 season a little. Now, I think it’s very, very important to be careful about analyzing partial data. It’s an easy way to get the stats to say what you want them to and the most accurate data is generally that which has the biggest sample size (so, unsplit data). As such, I try to be transparent when I do so.
Tanner Roark made 31 starts during the 2019 season. Over his first 27 starts, he produced 2.6 fWAR, 43rd-best in baseball through September 4th and right around the production of a handful of his fellow free agents—including Kyle Gibson (2.8), Cole Hamels (2.6), Michael Pineda (2.5), Wade Miley (2.1) and Homer Bailey (2.0).
Roark struck out 22.9% of the batters he faced, a touch above the league average for starting pitchers (22.3%), and walked 7.2% of his opponents, a touch below the league average (7.7%). He gave up 1.16 homers per nine innings he pitched, nearly identical to his 2017-18 mark (1.17) and much better than the average pitcher (1.44 HR/9). Plus, he gave up barrels at an exactly league-average rate (5.2%).
Over Roark’s final four starts of the season, he produced -0.5 fWAR, the second-worst mark among starters from September 5th on. His strikeout rate was down (19.8%), but so was his walk rate (5.8%), allowing him to run a nearly average K-BB% (14%). What ruined him over those four starts were the nine homers he gave up (4.42 HR/9), aided by ten barrels against (11.6% barrel rate).
If I was talking with Roark about signing with my team this off-season, I’d ask him if he had an idea as to what changed between his 27th and 28th starts. The question helps a team better understand what the issue might have been and whether Roark has a plan to deal with it. It also helps a team assess Roark’s self-awareness and ability to critique his performances, important traits for any athlete you are considering guaranteeing millions of dollars to. While they are far from the most popular guys in Toronto right now, I think Ross Atkins and co. are bright people who probably did touch base with Roark about how he ended his season.
One possibility is that he was hurt, not bad enough to take him out of the rotation, but bad enough to meaningfully affect his pitching. For most of the 2019 season, Roark’s four-seamer averaged around 92.5 mph. However, over his final four starts, his average velocity on the pitch dropped to 91.4 mph. A 1.1 mph drop isn’t huge, but it does take you from a little below average (38th percentile) to well below average (21st percentile).
Roark’s Statcast metrics on the pitch also got a lot worse at that point. Batters were generating an xwOBACON of .348 on his four-seamer up until September 4th, better than the league average (.409). Over his final four starts, batters produced a .782 xwOBACON against the pitch, the second-worst mark in the majors from September 5th on (min. 10 batted balls against one’s four-seamer). In contrast, batters produced a .406 xwOBACON against his other pitches before September 5th and a very comparable .388 xwOBACON from that day forward.
Obviously, one can’t definitively say that the decreased velocity on his four-seamer resulted in batters teeing off on it. But it is an interesting correlation. If this connection is vaguely accurate and the underlying injury has been resolved, Jays fans should feel a little more comfortable with Roark’s signing (though, to each their own).
One last thing I bring up purely as a curiosity is the fact that Roark’s 28th game was against the Astros at Minute Maid Park. He gave up three homers.
I’m not going to say that Roark’s first 27 starts are a better indication of what he will do in 2020 and 2021 than the full set of 31 starts he made last season, because I don’t know. I certainly hope so. Ultimately, after doing a bit of research on his 2019 performance, I feel a lot better about the signing. Hopefully that’s not just confirmation bias doing its thing.
Regardless, I’m under no illusions that the Jays have just added an ace to their rotation. I am still firmly in camp “go get Ryu”. As plenty have said, this signing works (and looks) a lot better is complemented with an even bigger SP addition. A Blue Jays rotation of Hyun-Jin Ryu, Roark and three of Matt Shoemaker, Chase Anderson, Ryan Borucki and Trent Thornton would be pretty solid, especially with guys like Nate Pearson, Anthony Kay and T.J. Zeuch waiting in the wings for their chance.
*Featured Image Courtesy Of DaveMe Images. Prints Available For Purchase.
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I’m an economics professor in the GTA whose lifelong love for the Jays was reignited by that magical August of 2015 and the amazing moments since.