Offseason Deep Dives: Jack Flaherty

Jack Flaherty was a relative afterthought in fantasy drafts last year, and understandably so.

He finally had a healthy season in 2023, making 29 appearances – 27 starts – and accumulating 144.1 innings between the Cardinals and Orioles. That came after he had a total of 154.2 frames from 2020 to 2022. The results weren't great, though. He did strike out 148 over those 144.1 innings, but his 22.8 percent strikeout rate was barely above the league average and his 10.2 percent walk rate, 4.99 ERA and 1.58 WHIP were downright ugly.

We did see Flaherty's ADP begin to tick up a bit after a strong Grapefruit League showing which saw him collect a 2.95 ERA, 0.98 WHIP and 26:4 K:BB over 18.1 innings. That said, we all know how dangerous it is to put too much stock into spring training results, and Flaherty was still amounting to merely a late-round flier who would be the first cut fantasy managers made at the first sign of trouble.

Those struggles never really came, at least not for an extended period of time. The highest ERA Flaherty had in any given month during the 2024 season came in April when he posted a 4.00 mark, and he had a sparkling 50:5 K:BB across 36 frames, finishing off that month with a career-high 14 strikeouts in a start against his former team, the Cardinals.

The dominant K-BB% continued for Flaherty throughout the season. Here's where he stacked up among qualifiers at the end of the year in that regard.

The only real change Flaherty made to his pitch mix in 2024 was eliminating his cutter, a pitch which he threw only 8.8 percent of the time in 2023 and was highly ineffective with a .390 xwOBA. His four-seamer (44.3 percent), slider (29 percent) and knuckle curve (21.8 percent) represented more than 95 percent of his repertoire. The velocity on each pitch was up slightly, although not enough to believe it was the impetus behind Flaherty's big bounce-back season.

While the velocity increase was minimal, Flaherty did get much better results with his four-seamer. The pitch earned a plus-5 Run Value from Baseball Savant after it registered at a minus-5 in 2023 and minus-8 in 2022. Additionally, for the first time in his career outside of a 21.1-inning sample from his rookie season, Flaherty got an above-average amount of vertical movement on his four-seamer as compared to pitches with similar characteristics. The whiff rate on his fastball in 2024 was 23.8 percent, which is the highest it's been since 2020 and better than it was during his stellar 2019 campaign.

The biggest factor in Flaherty's reemergence is that his command and control were simply way better. His walk rate in 2024 was 5.9 percent, which was easily a career best and nearly half of what it was in 2023. As you can see below, Flaherty's Location+ numbers, per FanGraphs, were better for all three of his main pitches, particularly his four-seamer.

Unsurprisingly, Flaherty being able to put the ball where he wanted with regularity allowed him to get batters to offer at pitches they shouldn't. His chase rate in 2024 ranked in the 72nd percentile, which was a career high. That's after it was in just the 12th percentile in 2023.

When Flaherty met with the Tigers during the free agent process, he noted that the mechanical tweaks they were suggesting were ones he had already identified on his own as something he needed to clean up. Those biomechanical adjustments obviously worked and were likely the driving force behind his improved command and control.

Flaherty's K-BB% with the Dodgers in September did slip to 17.9 percent, and he also had an up-and-down showing during the postseason, finishing with a 15:9 K:BB across 22 frames. It's possible the workload started to catch up to Flaherty, who, between the regular and postseason, threw 184 innings. That's 39.2 more than he threw in 2023 and just 12.1 off his career high from 2019.

It's also possible Flaherty's back wasn't 100 percent healthy. While he never went on the injured list this past season, he missed some time and received pain-killing injections on two occasions due to lower-back problems. Flaherty sported his worst velocity of the season in his final two regular-season outings, and his velocity fluctuated during the playoffs, as well. The Yankees reportedly pulled out of a trade for Flaherty at the deadline after their review of his medical records raised red flags about his back.

Flaherty remains unsigned as of this writing, but there have not been any whispers to this point that questions about the health of his back might be the cause for that. The right-hander has had other past injury concerns, as well, most notably shoulder issues that bothered him in 2021 and 2022. Flaherty hasn't dealt with any known shoulder problems in a while, though, and it does not seem he will have any trouble landing a lucrative multi-year deal, particularly since he's a relatively young free agent at 29.

Of more concern to me is where Flaherty lands, as going to an organization with a good reputation for getting the most out of their pitchers would leave me feeling much more confident he can back up his 2024 performance with a big 2025 campaign. Flaherty's NFBC ADP currently sits at 125.85, which leaves him 37th among starting pitchers. He finished 12th among starters in 2024, so there does seem to be some doubt about a repeat. Worth noting, though, is that free agents are usually discounted a bit due to uncertainty, so I'd expect Flaherty's ADP to tick up, particularly if he lands in a favorable situation.