How Jack Flaherty’s Fastball Development Unlocked Cy Young Potential

“The second I laid eyes on him on the mound, so many things came right out,” LaRocque recalls. “We knew Jack had a number of things in his favor. Very good fastball command for 18. Very good. Broad shoulders. Good arm action. A feel for his slider. He stepped on the field and he was one of the best athletes out there.

“He was as much a competitor right away as I’ve ever seen in the GCL. You saw him step on the mound with poise and intent, and it’s, ‘OK, here he is. I get it.’ I realized quickly: He’s going to move at a pace he will determine.”

Within four years, Flaherty went from a pitcher who didn’t crack the Top 20 Prospects ranking in the low Class A Midwest League to one of the finest second-half performances in major league history and a single-season strikeout total bested in franchise history only by Bob Gibson. His emergence as one of the finest young starters in baseball and on the short list for Cy Young Award favorites can be clocked by his fastball. Flaherty’s pace accelerated when it did.

In his first several years of pro ball, Flaherty threw between 89-92 mph, a solid but modest velocity given the industry’s preference for big arms when handing out big bonuses to high school righthanders in the first round.

The Cardinals provided a development map to Flaherty, who was already driven on his own. With patience, innings, and a fine-tuning of mechanics, his athleticism, they bet, would mature into more miles per hour. And that didn’t stop when he arrived in St Louis in September 2017.

Flaherty had never had a month when his fastball averaged greater than 94.2 mph until he had five faster months in 2019. He averaged 95.4 mph in his final nine starts as he polished a 0.91 ERA in the second half. No pitcher had ever pitched as many innings in the second half (99.1) and had an ERA lower than Flaherty’s, and no pitcher had ever had a second half like that as young as Flaherty, now 24.

For an industry that favors present velocity when scouting amateurs for the draft, Flaherty instead projected velocity. Actual velocity exceeded that.

In his final start of the year at Wrigley Field, Flaherty touched 98.7 mph.

“The jump in velocity—that’s just (from) getting bigger and stronger and growing up a little bit, and then refining some of the mechanical aspects,” Flaherty said in early July as he approached his first career Opening Day start.

“Going into 2017, it went up. Into 2018, it went up. And last year it went up as well. It wasn’t like I set out a goal to try to throw hard. The more I executed (my fastball) and located it, my confidence continued to grow.”

The Cardinals’ ability to draft, develop, and deploy homegrown pitchers has been the envy of the National League Central for almost a decade, once sparking an opposing NL scout to go on the record and say their process should be “evaluated and then emulated.”

Since 2009, the Cardinals have stocked and restocked their own pitching staff with the likes of Dakota Hudson (draft), Miller and all-stars Michael Wacha (draft), Lance Lynn (draft), Trevor Rosenthal (draft) and Carlos Martinez (international), and even populated other staffs with Marco Gonzales (draft), Joe Kelly (draft), Sandy Alcantara (international), Luke Weaver (draft) and Zac Gallen (draft).

Draft picks Ryan Helsley and Daniel Ponce de Leon are big arms developed from small schools.

The Cardinals have a sweet tooth for steady, top-conference college performers. Like any other club, they dig speed, but under executive John Mozeliak’s push, athleticism has been prioritized. One reason, Mozeliak explained, is because athletes have a better chance of learning, adapting and repeating mechanics at an accelerated rate while competing. It was Rosenthal’s play at shortstop and Kelly’s fast-twitch nimbleness that appealed to them—and hinted at untapped power that sharpened deliveries could unleash.

The Cardinals have seen other players jump in velocity such as closer Jordan Hicks, who went from power prospect to fire-breathing 102 mph sinkerballer at Class A. Rising reliever Kodi Whitley streamlined his mechanics to skyrocket from a low-90s fastball at low Class A to sitting 95-97 mph and touching 98 during a spring audition for the majors.

Flaherty personifies many elements of the process.

A gifted athlete, Flaherty had the baseline skills of fastball command, high aptitude and internal engine for competitiveness. He had what one coach called a “long-toss mindset” that fit within the Cardinals’ arm-strengthening approach, and Flaherty was hungry for analytics and how to better use them. He got by in the Midwest League on an ability to elevate a fastball and snap a slider for swings and misses. In those pitches, he and the Cardinals saw more to uncork.

Pitching coordinator Tim Leveque first watched Flaherty in Port St. Lucie, Fla., against the Mets’ GCL affiliate. Flaherty gave a five-inning look into his potential.

“Some guys you can go see for an inning and the stuff just pops,” Leveque says. “Some guys you have to watch, you have to see how they get through a lineup, and see how smart they are with their stuff. Jack you had to watch. Was (the velocity) a question early on? Yes. Yes, it was. But you could look beyond the 88 mile-per-hour fastball and see three, four years from now a fastball that was as fiercely competitive as he was.”

Echoed LaRocque: “This is just me as a scout: If he’s in the low 90s like that, with that command, that velocity is going to increase. His mindset was getting outs. He wasn’t fixated on velocity. He was fit for it to increase.”

The Cardinals prescribed a steady, deliberate increase in innings for Flaherty to get experience, and he arrived with a professional-honed appreciation for regimen. Both helped tease out more velocity. The plan was also to start him at low Class A Peoria, get him a taste of the level, and then scale him back to a short-season club in 2016. Flaherty “didn’t even bother with that model,” LaRocque said.

The righthander threw 95 innings for the full-season club, bounced to 134 innings at high Class A Palm Beach the next season and was ready for Double-A Springfield at the start of 2017. The idea was to scale up his workload as his strength matured and allow his feel for the game and physicality to grow concurrently, patiently. He hastened his progress by staying healthy, producing and untracking his delivery. Flaherty had a higher extension that made his fastball “sneaky” and changeup wily. It also could be harnessed for more horsepower.

“Part of the delivery question is, ‘Can you create more power?’ ” Leveque said. “You look at your legs, how you use your arm, and how can we create more power? Or better yet, how can we throw harder easier? That’s the question we ask. He was able to set that in motion.”

At the start of the 2017 season, Baseball America ranked Flaherty as the Cardinals’ No. 11 prospect—his first time outside the organization’s top 10 since he was drafted. The scouting report read how “although he has the look of a pitcher with more velocity to reveal . . . he’s yet to fulfill projections.” It took less than three months for him to get up to speed.

The same year he debuted at Double-A, he threw his first pitch at Triple-A, represented the Cardinals in the Futures Game and finished the year by staring the Cardinals’ season finale. He rose as swiftly as his fastball did. Jason Simontacchi, the former big leaguer and Flaherty’s pitching coach at Double-A, said it became “obvious early Jack was telling us that he needed to go up.” Pegged for 90-92 (mph) at the start of the year, he averaged 93.4 mph in the majors.

That was up to 94.3 mph in 2019, according to MLB Statcast, and in the final three months of the season—as he won back-to-back NL pitcher of the month awards—he hit cruise control at 95.4 mph. He went from having an average fastball in 2018 to an exceptional one in 2019, and along the way he kept that defining command. He got to the edge of the high dive, launched and kept his form.

“I definitely wouldn’t call it a leap of faith,” Flaherty said. “You work on command and you work on throwing to a specific spot, and when you get to throw harder it’s not about moving your body harder, it’s not about extra effort on your arm or your shoulder. If you keep your mechanics . . . you’re going to be able to repeat it and, more than likely, put it in the same spot, just a mile an hour harder. I don’t know the best way to describe the difference between throwing a ball 92 (mph) versus throwing a ball 97 in the exact same spot, but there’s a way to do it.”

A last thrust of propulsion came as Flaherty’s game coalesced in the middle of the 2019 season. Through tears, Flaherty insisted on making a start the day after the death of Angels starter Tyler Skaggs, his friend and fellow SoCal product. He would later say he felt unrestrained in that start, like he’d pitched with a tailwind that gave him direction. Flaherty had fought himself mechanically through the first few months of the season and felt his pitches stray off the plate or over the middle. He eased back a bit—before pitching coach Mike Maddux urged the opposite: put the pedal down. Trust it. Throw the fastball more. He did to better spots and with greater verve.

In his Sept. 19 start against the Cubs, Flaherty threw eight innings and allowed one run on three hits and struck out eight. That start was the third of five in September in which he pitched at least seven innings and allowed one or fewer runs. It also was a showcase of the velocity he could hit and the bandwidth he now had at his fingertips. He took a little velocity off, put a little movement on to show where he started. By the eighth inning he was revved to where he is now. He delivered a 98.6 mph fastball to the penultimate hitter he faced. His 118th and final pitch was 97.6 mph.

His 117th pitch of the game had been 97.9 mph.

All Flaherty’s work and discipline, all his elite athleticism—and all the Cardinals’ patience and planning—and the velocity once within reach was now in his grasp.

“I had not seen him throw a pitch, and by the time I was there on a GCL sunny day to see him step on the mound, I already knew he was paying attention, that he had a plan—and then you see his stuff,” LaRocque said. “You could look into the future and see what was possible, even at 18, and we had to be willing to let him advance as fast as his performance told us. And it did. Fastball command. Slider. Competitiveness. It was all there. It didn’t take long to add it all up.”

And up.

And up.