The Cardinals continued their pitching youth movement when they traded Mike Leake to the Mariners on Wednesday and announced that the club's No. 3 prospect prospect Jack Flaherty would come up and make his make his Major League debut on Friday. It's a well-earned promotion for Flaherty, St. Louis' 2014 first-round pick, who won't turn 22 until mid-October.
A former high school teammate of Lucas Giolito and Max Fried, both of whom have reached the big leagues, Flaherty had made a steady and fairly quiet climb up the Cards' organizational ladder, though the No. 53 overall prospect's numbers in 2017 have been a lot more impressive thanks to some steps forward in terms of his stuff.
Ever since his pro career began, Flaherty has been an intriguing combination of projectability and pitchability. In high school, he was a two-way player, playing the infield when he wasn't pitching. When his Harvard-Westlake team first went to the National High School Invitational, Fried was the ace and Giolito was hurt. Flaherty stepped up and pitched a huge game in the tournament, a feat he would replicate the following year.
Flaherty had a sense of how to pitch back then, even if it was with an average fastball. His command was uncanny for someone his age, and he had a very good changeup to go along with the heater, as well as showing an ability to spin the ball well. Combine that with a 6-foot-4 ideal pitcher's frame and it's easy to see why St. Louis took Flaherty No. 34 overall in 2014.
For the first couple of years, Flaherty's feel for pitching propelled him up while his overall stuff improved only modestly. He moved a rung per year, but he earned an in-season promotion from Double-A this year after posting a 1.42 ERA in 10 starts. Flaherty has been just as good since he moved up to Triple-A, especially after getting himself adjusted. After posting a 4.33 ERA in June, he's put up a 2.05 in July and 1.97 in August. For the year, Flaherty is 14-4 with a 2.21 ERA, a .221 batting average against and a 1.04 WHIP.
Flaherty has never been one to hurt himself with walks (2.6 BB/9 in his career), and he's continued that in 2017 with a 2.1 BB/9 ratio. He's given up almost a hit and a half per nine less this year compared to his previous two full seasons. What's been so impressive about Flaherty this year is that he's maintained his outstanding command while throwing harder than he has previously in his career.

Flaherty might have been slow to reach those projections, but he started to get there in 2017, hitting the mid-90s more consistently. He had always missed bats, about one per inning throughout his Minor League career, but he had done much of that in the lower levels because of his ability to keep hitters off-balance and guessing. Flaherty can still do that, but has more pure swing-and-miss stuff now, with an above-average changeup and slider at his disposal, not to mention a slow curve that gives hitters a fourth look.
Though Flaherty has already thrown a career-high 148 2/3 innings this year, based on how he's thrown this past month, it looks like he has plenty left in the tank. The Cardinals will understandably be cautious with his workload, but this should give fans an opportunity to get a few starts worth of a sneak peek into what the right-hander will look like at the highest level.
Flaherty doesn't typically try to do too much, sticking with his game plan. That's what got him to the upper levels of the system at age 21, and that's what will allow him to ride any ups and downs he might have. At one point, it looked like Flaherty's ceiling might be as a No. 3 or 4 starter. That's nothing to sneeze at. But with his uptick in stuff -- and who knows, there could still be more to come given his age -- to go along with his plus pitchability, he could be more of a front-line starter when all is said and done.