Jack is Back
Jack Flaherty resigns with the Detroit Tigers.
Intro - Contract Details
February 7th — The Detroit Tigers signed Jack Flaherty to a two-year, $35 million contract for the 2025-2026 seasons with a player opt-out after 2025. Flaherty will get a $20 million salary with a $5 million signing bonus this season. Then in 2026 his salary will start at $10 million and could increase to $20 million if he makes 15 starts in 2025.
Flaherty pre-Detroit
Flaherty, originally drafted by the St. Louis Cardinals looked like an ace in the making. In his age 22 and 23 season, Flaherty was excellent. 151 IP with 182 K and a 3.34 ERA in 2018. 196.1 IP with 231 K and a 2.75 ERA in 2019. It's a truly dominant stretch. The next four seasons tell a different story. Flaherty really struggled with health and quality production from 2020-2023. His stats over that period were: 4.12 ERA, 1.36 WHIP, 0.241 BAA, 273 K to 118 BB. Coming off 144.1 IP in 2023 (his highest since 2019), the Tigers took a chance on Flaherty in hopes of recovering some of that magic from 5 seasons ago.
Flaherty Becomes a Tiger (the first time)
Jack Flaherty signs a one-year, $14 million deal with the Detroit Tigers ahead of the 2024 season, slotting him into the starting rotation behind Detroit’s ace, Tarik Skubal. Flaherty’s first Spring Training outing came on Feb. 26, 2024, vs the Houston Astros. Only 1 IP, 0 H, 0 ER, 0 BB, 2K, a typical short outing to ease into the Spring workload. A strong inning of work, but not the main takeaway. His underlying metrics revealed an uptick in velocity across all his pitch types. Maybe just added adrenaline in his first start with his new club or an immediate positive impact from Chris Fetter and the rest of the pitching staff.
Let’s flash forward to his March 19th start vs the Philadelphia Phillies as his workload increased and changes became more noticeable. His final line: 5 IP, 4 H, 0 ER, 0 BB, 7 K. Once again, his pitch velocity increased on his 4-seam fastball, slider, and knuckle curve, along with a 36 CSW% (called strike or swinging strike). Flaherty finished Spring with 18.1 IP, 14 H, 6 ER, 4 BB, and 26 K. Tigertown was buzzing with the hopes that Flaherty’s skillset from his first few seasons had resurfaced. The real test would come once the regular season started against lineups full of major league hitters.
Flaherty’s first regular-season start for Detroit came on March 31st vs. the Chicago White Sox. He finished with 6 IP, 4 H, 1 ER, 0 BB, 7 K, and a 33 CSW%. A very impressive debut, answering any questions Tigers fans might have had coming out of Spring. However, he followed that up with an underwhelming second start vs Oakland, finishing with 6 ER over 6 IP. One good and one bad start to his Tigers career left Tigers fans doubting again. Would this just be an inconsistent season like much of his career? Was Spring just a flash in the pan vs non-major league hitters?
From mid-April through May, Flaherty had eight starts. All but one qualified as a quality start (more than 6 IP and less than 3 ER), while 5 of the 8 were 6+ IP with 9+ Ks. It was a dominant stretch that not only validated the Tiger's move to acquire Jack in the offseason but put him atop most trade target lists for contending teams at the MLB trade deadline. One start that really stood out for me was on April 30th vs his former team, the St. Louis Cardinals. His line: 6.2 IP, 2 H, 0 ER, 1 BB, 14 K, with 24 whiffs on 93 total pitches and a 46% CSW. Extra motivation against the team he debuted with in 2014 that then later traded him away.
Old vs New
I want to dive into the details behind Flaherty’s return to stardom since joining the Tigers organization. On the surface, he increased his K% (from 22.8 in ‘23 to 29.9 in ‘24) and decreased his BB% (from 10.2 to 5.9). Striking out more hitters, while walking less is always going to lead to success. He also changed up his pitch mix slightly too. In 2023, he threw six pitches (a four-seamer, slider, knuckle curve, cutter, changeup, and sinker). Whereas in 2024, he dropped the cutter completely and relied more heavily on his four-seamer, slider, and knuckle curve. It was the slider and knuckle curve that saw the most drastic changes. I’ve highlighted some of the more impactful changes below from his pitch-tracking data on BaseballSavant. The slider became a real weapon for generating whiffs, while both the slider and knuckle curve were used more to put away batters.
Flaherty saw several plate discipline metrics improve from ‘23 to ‘24. Out-of-zone % and out-of-zone swing % went up, meaning not only was he placing more pitches outside of the strike zone, but he was getting opposing hitters to swing at those pitches more often. First-pitch strike % and first-pitch swing % also improved, meaning he started hitters off behind in the count more frequently, lots of times, by getting them to swing at that first pitch more.
World Champ & Return to the Motor City
Flaherty, along with Fetter and the Tigers pitching staff, made pitch mix changes that helped resurrect his career. The Tigers took advantage of his aforementioned trade value and sent him to the LA Dodgers for their No. 8 and No. 22 prospects (Thayron Liranzo and Trey Sweeney). Flaherty went on to win the 2024 World Series with his hometown team, while the Tigers got two pieces for the future. In fact, Sweeney has already had a couple of key moments with the Tigers during their stretch run into the postseason to end 2024.
The Tigers have built a respectable pitching development and analysis program, with Flaherty being the most recent example of that. Fetter and the staff liked what they saw from Jack enough in 2024 to encourage the front office to re-sign him again this season. I was encouraged by what I saw in his first stint with Detroit, and I think he can improve on those results this year. The 1-2 punch of reigning AL Cy Young winners Tarik Skubal and Flaherty will be fun to watch throughout the upcoming baseball season.