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An Examination of Jack Flaherty’s First 3 Starts

After settling into his third start, Jack Flaherty may have shown us his path to success and what that success might look like.

St. Louis Cardinals v Milwaukee Brewers Photo by John Fisher/Getty Images

The rotation has been the St. Louis Cardinals biggest weakness so far this season, with the group ranking 24th in ERA and 19th in fWAR. Someone who has provided a boost to that ERA is Jack Flaherty, who currently has a sterling 1.76 ERA through 3 starts, despite an ugly 13-to-14 strikeout-to-walk ratio.

So what can we make of that? I want to find out by examining each of Flaherty’s first 3 starts and see where he’s made progress and where he’s struggled.

Start #1 - 5 IP, 0 ER, 7 BB, 4 K

What a weird line this is. Talk about getting into trouble and working out of it. As you may expect, Flaherty struggled to throw strikes as he threw only 44% of his pitches zone. But that problem was expounded by the fact that the right-hander only enticed a swing on 9% of the pitches that he threw out of the zone.

So problem #1 is that Flaherty couldn’t find the zone and problem #2 is that he wasn’t deceptive enough to make up for a below average zone rate.

Sometimes those numbers go hand-in-hand and other times they don’t. In this instance, I’ll argue that Flaherty’s difficulty finding the zone really compounded his lack of deception.

There are 2 reasons for that:

  1. He often missed the zone by so much that hitters weren’t enticed to swing
  2. He often worked from behind so hitters could be more selective

Flaherty struggled to establish the fastball (49% zone rate, 5% oSwing%) and that made his slider less dangerous. He threw his go-to breaking pitch in the zone only 43% of the time but that’s about an average rate for Flaherty, or maybe only a percentage point or two below the norm.

Usually sliders make up for a lower zone rate by getting chases outside the zone but Flaherty’s inability to establish his fastball limited the oSwing% of his slider to just 19%.

Notably to my eye, Flaherty’s fastball command was really inconsistent and he sometimes had to revert to a slider or curveball to get a first pitch strike, even though his breaking pitches actually landed in the zone at a slightly lower rate than his fastball.

I honestly have no idea how Flaherty was able to get through 5 innings, much less 5 scoreless innings, but he deserves a lot of credit for the way that he battled and got himself out of trouble.

With that being said, after this start, I was concerned about Flaherty’s fastball specifically as it had much more sink (20 inches of drop), averaged only 91 mph, and wasn’t commanded well at all.

Start #2 - 5 IP, 2 ER, 6 BB, 3 K

Flaherty’s second start brought more of the same, statistically speaking, minus the shutout performance. While this line doesn’t look great, there were some positives to take away.

To begin with, Flaherty gained almost 3 ticks on his fastball, improving his average velocity to 93.8 mph, and he even ran a fastball up to 96.1 mph. He also gained an extra 2 inches of ride with the pitch, bringing his average vertical break to 18 inches, but that’s still a far cry from the 15.1 inches of vertical break the pitch had in Flaherty’s excellent 2019 campaign.

Despite the improved fastball, though, the right-hander still struggled to establish his command of the pitch throughout the game.

Beyond that, it was more of the same. The only other notable change is that Flaherty incorporated his cutter more, throwing 17 cutters after throwing just 2 in his first start.

The stats may have been worse in this outing but there at least one small step forward as Flaherty regained some velocity. Beyond that, though, I wasn’t thrilled by this performance. Lack of command is concerning, especially when a pitcher still clearly doesn’t have his best stuff (whiff rate below 25% in each of his first 2 starts).

Start #3 - 5.1 IP, 1 ER, 1 BB, 6 K

Before I even say anything else, from the numbers you can tell that this start may be a turning point for Jack Flaherty. I shouldn’t have to tell you that his command was better, but I will anyways.

Flaherty found the zone 55% of the time with his slider and 56% of the time with fastball. He mixed in some knuckle-curves, cutters, and changeups, but, combined, those 3 pitches made up less than a quarter of his arsenal.

What Flaherty did differently this game, besides find the zone more often, is throw his slider more than his fastball (45% slider usage, 32% fastball usage). And that worked wonders for him.

Opposing hitters swung at 55% of his sliders out of the zone and whiffed at a 37% rate against his slider. That was his money pitch. His velocity remained up across the board and his movement profile stayed mostly the same with each pitch.


I really have 3 main takeaways from Jack Flaherty’s first 3 starts, and after going through each of them individually, you probably already know what they are.

For starters, he needs to throw strikes. That’s pretty simple. And to be even more specific, he needs to throw strikes with his fastball. And to be even more specific, he needs to throw his fastball in the zone consistently because hitters simply aren’t willing to chase the pitch outside the zone (5.6% chase rate). Even in his last start when Flaherty was doing a better job of locating his four-seamer, the pitch had only enticed chases at a rate of 8%.

In his third start, his main pitch may have been slider but he’s not going to survive for long if he can’t put his fastball in the zone.

The reason for the lack of chases, and the decreased whiff rate (15.4% whiff rate), is likely the movement profile of the pitch. It doesn’t really run, it doesn’t rise, and it doesn’t really cut. It’s simply straight with some sinking action. In fact, there are times when the pitch has actually profiled as almost a hard cutter with less drop.

The easiest comp for me to come up with is Andre Pallante, whose fastball averages 20.6 inches of drop and only 2.2 inches of run. Through 3 starts, Flaherty’s fastball is averaging 19.3 inches of drop and 2.2 inches of run.

The similarities are incredible.

So, with that in mind, what does Andre Pallante do really well? He gets ground balls. Do you know what Flaherty has done well this year? Get ground balls. Do you what Pallante’s fastball doesn’t do? Get whiffs. Do you know what Flaherty’s fastball hasn’t really done? Get whiffs.

Flaherty has always been a fly ball pitcher. In fact, his career ground ball rate is just 41.3%. But this year, it’s 54.1%. His 15.4% fastball whiff rate would also be the lowest of his career except for his first season in the majors in 2017 when he threw 105 fastballs and got a 10.7% whiff rate with the pitch.

Are we going to make conclusions after just 15.1 innings? Absolutely not. But Flaherty’s fastball is looking a lot like Pallante’s and that means that we could get some Pallante-esque performances from Flaherty this year.

His fastball could still rebound and show it’s old 2019 shape, but that simply doesn’t seem likely to me with how much time has passed. And I wonder if Flaherty’s early struggles to command his fastball are due in part to him getting used to the different shape of the pitch.

My second takeaway is that Flaherty should throw more sliders, and, to be more broad, he should throw more breaking balls.

The 27-year-old simply hasn’t shown a dominant fastball this season. And, again, that may change, but he’s better off going with a slider heavy approach and supplementing with some knuckle-curves.

His slider is going to be a pitch that he needs to use to get whiffs becuase if there’s one thing we know about Pallante’s fastball (and, thus, Flaherty’s fastball by extension), it’s that it doesn’t get whiffs. That may change, but it also might not and if Flaherty’s fastball shape doesn’t change, I wouldn’t be shocked to see the pitch’s whiff rate sit right around 15%.

So, for Flaherty to get strikeouts, he simply can’t be a fastball heavy pitcher. I want to see him throw his fastball less than 50% of the time, and, honestly, I wouldn’t complain if he only threw it 40% of the time.

The downward action on the pitch may help Flaherty get grounders, but it’s going to be the right-hander’s breaking pitches that help him get whiffs.

And that leads to my 3rd takeaway, which is that we shouldn’t be surprised to see Flaherty be a different pitcher this year. And I don’t necessarily mean that in a bad way. It’s simple. If he doesn’t recover his fastball shape, then his numbers will look different as a result.

The early version of Jack Flaherty is one with a lot of walks, a lot of grounders, and not a ton of strikeouts. I don’t think all of these results will hold, but I do think Flaherty can shock us all and maintain a groundball rate above 50% if his fastball maintains the shape it’s shown early on this year. I also think he can miss more bats if he continues to use his slider like he did in his third outing.


It’s still too early to make any hard conclusions as to what kind of a pitcher Jack Flaherty will be this year but he may have turned a corner in his third start.

My general impression of Jack Flaherty through 3 starts is that he’s a different pitcher now than he was in 2019. His last outing has me encouraged (but not totally convinced) that he can pitch effectively and maybe even be one of the better starters in the rotation but I expect his production to look different this year with more groundballs and fewer strikeouts. Thus, you can see just how important command will be for him if he isn’t going to miss as many bats.

Thanks for reading, VEB. Have a great Sunday.