Don’t underestimate Cardinals rookie Jack Flaherty

Tonight the St. Louis Cardinals will send rookie right-hander Jack Flaherty to the mound for his second major league start against the San Diego Padres. His first MLB start against the San Francisco Giants on September 1st was a bit rough: eight hits and five runs in four innings pitched, although he did strike out six men with just one walk. Flaherty is only 21 years old, had an outstanding minor league campaign, and should not be underestimated.

The Cardinals drafted Flaherty in the first round in 2014, 34th overall, out of high school in Studio City, California; he was teammates there with White Sox rookie Lucas Giolito and Braves prospect Max Fried. Although Flaherty didn’t receive quite as much pre-draft hype as his predecessors, he quickly emerged as a top prospect in pro ball, dominating rookie ball and Low-A.

His 2016 season in High-A was decent enough (3.56, 126/45 in 134 innings) and he ranked fifth on the Cardinals Top 20 prospects list entering 2017 with this comment:

5) Jack Flaherty, RHP, Grade B: Age 21, compensation pick in 2014, posted 3.56 ERA with 126/45 K/BB in 134 innings in High-A, 129 hits; fastball in 90-93 range plays up due to strong change-up and improving breaking stuff, throws strikes, very efficient for his age; can hit inside and outside corner, pitches fearlessly; will transition to Double-A in 2017 but Cardinals are not in a position where they have to rush him. ETA 2019.

Major league roster needs aside, Flaherty was so good in 2017 that he advanced that timetable, blowing away Double-A (1.42 in 63 innings, 62/11 K/BB) and succeeding against older competition in Triple-A (2.74, 85/25 in 85 innings). Won-Loss record means nothing as far as prospect analysis goes but his combined 14-4 line this year is certainly pretty to look at.

He’s as fun to watch in person as he is on the stat sheets. Flaherty’s fastball has kicked up a notch over the last year, as he now works at 91-95 (with peaks at 96) instead of 89-93. At his best Flaherty makes experienced hitters look foolish by mixing low-to-mid-90s heat with secondary pitches that can dip into the mid-70s.

In Triple-A he showed the ability to paint all quadrants of the strike zone with a plus change-up, while his slider and curveball showed more definition than in past seasons.

Although Flaherty is unusually polished for a pitcher his age, he’s not perfect. His control (avoiding walks) is still a bit ahead of his command (hitting spots within the strike zone) and he will make the occasional location mistake, leaving him vulnerable to home runs at times. While the increase in velocity his year improved his margin for error, he still has some finishing touches to make. That should just be a matter of experience.

Well-built at 6-4, 205, Flaherty repeats his mechanics well and has a relatively low-effort delivery. That’s no guarantee of health, of course, but so far he’s been very durable.

The general consensus sees him as a future number three starter. That’s a fair assessment, but if Flaherty gains additional velocity or sharpens his command a bit more, he could exceed those expectations.