Jack Leiter’s Increased Fastball Velocity A Positive Sign Early In Spring Training
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Early spring training velocities are ripe for overreaction. A pitcher may show up with a little less velocity and then round into form. Another may spike a bit of velocity that doesn’t hold up over the course of a long season.
So we don’t want to overreact too much over anything when the calendar still reads February.
That being said…Rangers righthander Jack Leiter’s first outing of the spring was encouraging.
In one inning of work, Leiter sat at 98 mph with his four-seam fastball while touching 100 (99.9 mph to be precise). Every one of his four-seamers was 98 mph or harder. He didn’t throw a ton of strikes with it in his first outing, but that velocity jump is very useful, because the difference between Jack Leiter at 98-99 mph and at 96-97 mph is stunning.
Leiter is also working on adding a sinker, which could also help his four-seam fastball play better by giving hitters something else to worry about.
Leiter has always had a problem with his fastball being too hittable in the big leagues. He walks a tight rope, as it’s a pitch that gets him plenty of swings and misses, especially up in the zone. But it’s also the pitch that can get crushed when he doesn’t locate it perfectly.
Last year in the major leagues, opponents hit .338/.429/.612 against Leiter’s four-seam fastball. In the minors for his career, Synergy Sports’ logs have opponents hitting .258/.398/.479 against his heater (for the minors, we didn’t select four-seam fastballs, as the pitches are sometimes just logged as fastballs).
But Leiter’s four-seam fastball is really two different pitches depending on his velocity. When he gets to 98+ mph, he succeeds. In the minors from 2022-24, Leiter threw 146 fastballs 98 or above. On those fastballs, opponents hit just .128/.239/.205 with three doubles and no extra-base hits in 46 plate appearances. He had a 36% swing-and-miss rate on those fastballs.
Leiter had the same success at 98+ in his 2024 big league stint. He threw 60 fastballs 98+ mph in the big leagues, with opponents hitting .167/.200/.222 against him with one double and no other extra-base hits in 20 plate appearances. He had a 31% swing-and-miss rate.
This is not a case of arbitrarily picking out a cutoff point. If you look at 97 mph fastballs alone, minor league opponents hit .327/.377/.551 against him over 223 pitches and major league opponents hit .318/.407/.591 over 99 pitches.
On his 91-97 mph four-seam fastballs, big league hitters feasted to the tune of a .390/.493/.746 line. Leiter still had a 28% swing-and-miss rate, but he gave up nine extra-base hits, including four home runs, in just 76 plate appearances.
The minor league numbers haven’t been much better. Opponents hit .317/.435/.572 against Leiter fastballs in the 91-97 mph range in the minors, with 28 extra-base hits including 12 home runs in 256 plate appearances.
We’ll have to see if Leiter can maintain the velocity he showed in his first spring outing. But if he can, he’s a much more effective pitcher when he’s flirting with triple digits than he is when he’s sitting in the mid 90s.
