A Change of Scenery Has Worked Well for Jack Flaherty

While Tarik Skubal has pitched his way into the Cy Young conversation, Jack Flaherty has done his share of the heavy lifting when it comes to helping the Tigers toward respectability. After years of battling injuries, capped by a rough campaign that included a mid-year change of address, the 28-year-old righty is in the middle of his best season in half a decade thanks to another change of scenery. He also should generate plenty of interest ahead of the July 30 trade deadline. On Saturday, Flaherty turned in five shutout innings in a blowout of the Astros, his third consecutive scoreless outing.

Flaherty’s 16.2-inning scoreless streak hasn’t gone entirely smoothly, but it began in impressive fashion. On May 30, he no-hit the Red Sox for 6.1 innings before allowing a single to Rob Refsnyder, then retired one more hitter before departing. On June 4, he threw five shutout innings against the Rangers, allowing two hits and no walks, but exited after 60 pitches due to lower back tightness. At the time, he described the early exit as “more precautionary than anything,” having pitched through a bout of tightness he felt prior to taking the mound. Instead of taking his next turn, he received an injection of some kind (not cortisone) on June 10, and recovered well enough to take the mound this past Saturday. He pitched well, allowing just three hits (including a double and a triple) and a walk, and striking out six. He exited after throwing just 73 pitches, in part because the Tigers led 10-0 at that point; he had struggled to find a rhythm due to the long delays between innings as Detroit pummeled Houston starter Spencer Arrighetti and reliever Shawn Dubin in what ended as a 13-5 rout.

Though Flaherty’s four-seam fastball averaged just 92.2 mph, down 1.4 mph from his seasonal average, he generated five of his six strikeouts with the pitch, four via called strikes; his CSW% (called strike and walk rate) for the pitch was 38%. He struck out Jose Altuve twice, once chasing a knuckle curve and once looking at a 95.3-mph fastball; the latter was his fastest pitch of the game as well as his final one.

“I’m in a good spot,” said Flaherty afterward. “I’ll just continue to evaluate it day by day and see how I keep going.” Regarding his fastball, and particularly the final one to Altuve, he said, “It just meant that I still had some in the tank as the game went along… Sometimes, you get up 10-0, and it was just fill up the zone, let them put it in play and get back to the dugout.”

“I’m not talking about velo,” Hinch told reporters regarding Flaherty’s outing and particularly his fastball. “For him, it’s the finish on his pitches, the characteristic of it, the funny swings and misses, the takes with two strikes tell me a lot about the fastball more than the velo does.”

Thanks to Flaherty’s streak, he’s now third in the AL with a 2.62 FIP, sixth with 2.2 WAR, and ninth with a 3.01 ERA in 77.2 innings. That’s a huge improvement from last year, when he posted a 4.96 ERA and 4.36 FIP in 144.1 innings, first with the Cardinals and then the Orioles, who traded three prospects for him at the August 1 deadline. Baltimore bumped him from the rotation to the bullpen in mid-September, and he finished the season with a 6.75 ERA.

The major positive for Flaherty’s 2023 season was his health. His 27 starts were his most since 2019; he made just 32 combined from 2020–22 due to the pandemic-shortened season, an oblique strain, and recurrent shoulder woes, landing on the 60-day injured list three times in that span. That better health — and some post-trade improvement of his fastball, albeit with his slider and curve regressing somewhat — helped him net a one-year, $14 million deal from the Tigers, with another $1 million possible in incentives.

The most surprising aspect of Flaherty’s performance this season is his career-high 33.3% strikeout rate, which is second only to Garrett Crochet among AL qualifiers. That’s 3.4 percentage points ahead of his previous personal best, set in 2019, and 10.6 points ahead of last year, making it the biggest year-to-year jump in the majors:

Interestingly enough, the majority of those pitchers — all but Dunning, Schmidt, Suárez, and Singer — are with different teams than the ones with which they started the 2023 season, a reminder that new surroundings, new voices, and new ideas are sometimes necessary to restore or improve players’ performances. Meanwhile, Flaherty has walked just 3.7% of batters, the third-lowest mark in the AL; his 29.7% strikeout-walk differential is second in the majors, 0.1 percentage points behind Crochet.

Not only has Flaherty cranked up his strikeout rate, he’s also generated a 44.6% groundball rate, his highest since his 2017 rookie campaign. I’m a big fan of that combo; a few years ago, while writing about Luis Castillo, I tapped into our then-new “Plus Stats” — specifically our league-indexed strikeout and groundball rates — to produce something called KGB+, a quick-and-dirty measure that shines a light on pitchers who combine strikeouts and groundballs, which is generally a good strategy for success, if not the only route there. Flaherty entered Monday ranked fourth in the majors by that measure:

At the center of the Flaherty revival is the offseason work he did with Tigers pitching coach Chris Fetter and assistant pitching coach Robin Lund, who helped him clean up his mechanics, improving his ability to repeat his delivery. From the Detroit Free Press’ Evan Petzold on May 22:

Flaherty didn’t have a good feel for his slider last season because he struggled to repeat his delivery, and he struggled to repeat his delivery because he wasn’t moving his body down the mound the right way. He tried to make adjustments throughout last season, but the problem kept getting worse.

Optimizing the way his body moves through muscle activation was the primary focus of his offseason work. He used to rely on his quadricep muscles to travel down the mound, but now, he focuses on his posterior gluteal muscles and his hamstring muscles…

“It’s allowed me to have a little bit better velo and stay behind the ball and be a little bit more true on my heater,” Flaherty said, “and then be able to repeat my slider over and over and throw it a little bit harder. I can just feel the sharpness of it when it leaves my hand, which is something last year I didn’t really feel. I felt like it rolled. It never had any bite to it.”

Flaherty also noted that the coaches made one small adjustment with the grip on his slider when he got to spring training. With the changes, he’s increased the average velocity of his four-seamer by 0.5 mph (from 93.1 to 93.6) and of his slider by 0.7 mph (from 84.2 to 84.9). He’s getting a bit more ride and more break on the fastball, but a bit less movement in both planes on the slider:

I’ve thrown 2019 into the mix because that season represents Flaherty at his peak, whereas last year probably represents him at his worst over a full season, as opposed to his injury- or COVID-shortened ones. I’ve omitted comparisons of his other major secondary pitch, his knuckle curve, because its characteristics haven’t changed as much.

Because his velocity is unremarkable, neither of the pitch-modeling metrics that we host, Stuff+ or PitchingBot, grade either Flaherty’s four-seamer or slider as average or better in terms of stuff, and they’re not consistent about whether the two pitches have actually improved from 2023, though both see his command of the two offerings as well above average. I’m skipping the numbers because a comparison of his heat maps for the pitch amply illustrates how much better a job he’s doing at keeping it out of the center of the strike zone:

Here’s a look at the results, again throwing in 2019 for comparison’s sake:

Thanks to his mechanical changes, Flaherty has lowered the wOBA against his fastball by 70 points relative to last year and against his two breaking pitches by more than 100 points. He’s generating whiff rates above 40% against both breaking pitches, with the whiff rate on his slider increasing by nearly 15 points and that of his fastball increasing by over six points. His results on these three pitches may not be as impressive as those from 2019, but he’s certainly in a much better place than he was last year.

As suggested by the highlighted cell in the usage column, Flaherty has increasingly called upon his slider; he throws the pitch to batters of either hand with similar frequency, and likewise for the curve. He has completely ditched the cutter that he threw 9.1% of the time last year in favor of more four-seamers and sliders, and he’s pretty much abandoned his sinker, throwing it 2% of the time last year and 1.7% of the time this year, compared to 11.9% circa 2019. With this new mix, Flaherty has been much more effective against hitters of either hand. He’s lowered his wOBA against lefties from .372 to .268 and against righties from .337 to .283.

Because of his bounceback, Flaherty has already justified his salary in a dollars-to-WAR sense. With the Tigers (34-38) running sixth in the AL Wild Card race, six games out of the third spot and with Playoff Odds of just 9.8%, it will be interesting to see how they approach the trade deadline. There may be buzz about trading Skubal, who has two years of club control remaining after this one, but dealing a homegrown pitcher who has evolved into a staff ace and still has affordable years ahead of him seems quite counterproductive; you’re hoping to hold onto pitchers of Skubal’s caliber for when you’re ready to contend.

Flaherty, on the other hand, could be viewed as a rental whose value they’ve quickly restored; if he netted three prospects in the 35-40 FV range last summer when he was scuffling, the return for the Tigers ought to be more substantial while he’s pitching well, and he could very well wind up as the top starter available. On the other hand, given how well he’s meshed with Detroit’s coaches, perhaps he’s open to an extension. But regardless of which direction he goes, Flaherty’s turnaround has been an impressive one.