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Sean Sullivan Turning Heads with Deceptive Delivery

May 7, 2024

Keep the ball up. That sounds like pitching heresy, a sure way for a starting pitcher, particularly one with rather unexceptional velocity like Sean Sullivan, to get hit … and get hit hard … and stumble ineffectively through short outings. Sullivan defies that thinking and succeeds. Otherwise, the Rockies would

Keep the ball up.

That sounds like pitching heresy, a sure way for a starting pitcher, particularly one with rather unexceptional velocity like Sean Sullivan, to get hit … and get hit hard … and stumble ineffectively through short outings.

Sullivan defies that thinking and succeeds. Otherwise, the Rockies would not have taken the left-hander in the second round, 46th overall, of the 2023 First-Year Player Draft out of Wake Forest.

Keep the ball down has long been a guiding pitching principle. Or in the poetic jargon of the game: throw peas at the knees. That homespun advice, old as it is, arrives with an audible splatter of tobacco juice.

Keep the ball up? That’s not quite a mound mantra for Sullivan. But it’s where his fastball thrives and the ideal spot for it. Rockies Pitching Strategist Flint Wallace called Sullivan “a unicorn” and said he’s “extremely unique” because of a rare combination of two atypical attributes.

Sullivan, 21, has an unusually long extension down the mound and a very low release height of his pitches. Because of how little Sullivan has pitched professionally, he is still something of a curiosity to the Rockies. They are still learning about him. That’s why Minor League Pitching Coordinator Doug Linton labeled Sullivan as “an intriguing guy.”

In one of Sullivan’s two instructional league appearances last fall, Linton was seated behind the plate next to Wallace, who had a radar gun trained on Sullivan.

He was facing a Diamondbacks lineup that wasn’t the usual assortment of raw professionals recently out of college or high school or the Dominican Summer League. The Diamondbacks were then in the postseason. They were using the instructional league as a taxi squad, keeping various 40-man roster types and players with Triple-A and Major League experience active should they be needed.

Linton watched with amazement as the Arizona hitters were unable to make contact. He assumed Sullivan’s fastball was 94–95 mph and turned to Wallace for confirmation, only to learn the pitch was 91–92 mph.

“And you’re just like going, ‘This is unbelievable,’” Linton said. “He was facing Major League hitters that weren’t touching him.”

Asked whether he knew he was facing a very atypical Diamondbacks instructional league lineup, Sullivan had an interesting answer.

“Honestly, I don’t know if it’s good or bad, but I don’t really pay attention to the hitter too much. I think it’s a little bit different when it comes to (digesting) scouting reports. But in (instructional league), when you’re out there working on your craft and just trying to get some experience, I’m not really worried about what affiliate they were at or anything like that. I just go out there and attack.

“But I actually do remember hearing about the taxi squad guys (after the outing). I think it’s very cool. I like trying to face the best competition. I think that was a very cool opportunity just because it’s not very often you get to face guys who are up and down (from the Majors).”

There is a mystique to Sullivan that simply doesn’t exist with other Rockies pitching prospects. Part of that mystique comes from his minimal professional experience — two innings total in two games with the Rockies’ club in the Rookie Level Arizona Complex League and two innings in one game at Low-A Fresno.

In those four innings, Sullivan did not allow a hit or a run, walked one and struck out 10.

In his two instructional league outings — two innings against the Cubs and then two against the Diamondbacks — he struck out the side in the first three innings and struck out the first two Diamondbacks to make it 11 straight strikeouts before the final Arizona batter fisted a weak pop up to the right side.

That’s a limited body of work, to be sure. But it’s enough to reveal some rather unique metrics and invite some thoughts that while not outright sinister are somewhat unusual.

“It’s a harder slot (for hitters to track the ball),” Rockies Director of Player Development Chris Forbes said of Sullivan’s arm slot that sits somewhere between low three-quarters and sidearm. “Very controlled delivery, but the deception in that delivery just creates this hard angle on hitters. It just makes his fastball almost invisible.

“At some point, he’s going to get squared up. That’s baseball. You just kind of almost want to be in the yard if that happens just to see what’s going on, see how they’re doing it.”

There are various ways to describe fastballs. Nasty, filthy, overpowering, late-moving, riding and unhittable typically pertain to power pitches, fastballs thrown at high velocity, say 95 mph and up. And the pitchers that throw them are respectfully said to have big arms.

But nearly invisible? And with rather pedestrian velocity? Being something of a mound outlier helps Sullivan achieve what appear to be smoke-and-mirrors results.

The average extension for a Major League pitcher on his fastball, Wallace said, is 6 feet, 4 inches. Sullivan’s extension on his fastball has gone as far as 7 feet, 4 inches, or a full foot farther down the mound beyond the Major League average, Wallace said.

And Sullivan is usually right between 7 feet and 7 feet, 2 inches, Wallace said. And it’s not as if Sullivan has the height advantage of, say, Randy Johnson, a Hall of Fame left-hander who not only threw exceptionally hard but had a 6-foot-10 frame, making it appear to the hitter he was frighteningly close when releasing the ball.

Sullivan is 6-foot-4, so he lacks a menacing stature. But he’s averaging 8 to 10 inches more extension on each of his pitches than hitters are used to seeing.

“So that makes his fastball, even though it’s 91–92 (mph), it probably plays like 96–97 (mph),’ Wallace said. “Because the hitter doesn’t realize he’s releasing it 10 inches closer (than most pitchers). They’re still timed up from the average of where they see a ball released, so it’s getting there eight to 10 inches quicker at 91 (mph) than every other 91 (mph) pitch.”

Sullivan has pinpoint command with his fastball. And that ability to put the pitch where he wants is another benefit of his unusually long extension.

“When you create that extension, that means by the end of the release I am driving the ball straight towards my target,” Wallace said. “There’s no doubt about that. There’s no cutting through the release point. There’s no getting around it.

“Because of that extension, he’s further out front. You’re having to finish driving the ball in a straighter path with your hand, even if it’s (from) a low slot. … It matters at the end. I’m moving my hand in a direction towards my target because of that extension.”

Wallace said the average Major League pitcher’s release height is 69.3 inches, or just over 5-foot-9. He said Sullivan’s average release height is only 5-foot-2, seven inches below the Major League average.

“So the height of his pitch is lower, but his pitch doesn’t sink from that arm slot,” Wallace said. “He’s almost straight sidearm, and it doesn’t sink. So it stays true. And what that means is when it gets to home plate, it has a very flat approach angle. So it’s not going down. (All pitches are) moving down because of gravity, but it’s moving at less of an angle. So guys are expecting it to drop from the arm slot (he has). And it doesn’t, so they just swing under it all the time.

“It’s an optical illusion from what they think the ball’s going to do.

Because of his arm slot, it does something different.”

Taller pitchers with a higher release height are typically taught to throw with a downward angle and drive the ball to the bottom of the zone.

“So they make that a steeper angle as (the ball) crosses home plate,” Wallace said. “Steeper than the bat angle could be. So what we’re looking for is something to be flatter or steeper than the attack angle of the bat coming through the strike zone.”

Flatter is rarer. So Sullivan, with his ordinary fastball velocity that plays up because of his longer extension and his lower release height, is able to pitch up in the zone and have hitters swing under his fastball.

“For somebody like Sullivan to throw down,” Wallace said, “then that means the angle comes in at the bottom of the zone is matching bat plane for a vast majority of the guys.”

Wallace said that left-handed closer Josh Hader, now with the Astros, also has the ability to pitch up in the zone, albeit doing so with more velocity than Sullivan.

“But he has that same ability to throw the ball at the top of the zone, and everybody swings under it,” Wallace said. “And when he throws at the bottom of the zone, he can get hurt.

“I’m not saying they never go down there, but it’s more to freeze the hitter. It’s a freeze pitch or change an eye-level pitch. We always think change eye-level is throw it up. For these guys, it’s actually throw it down and then go right back up.”

Once again, that highly unusual key to success: keep the ball up.

Sullivan said he has always thrown with his low arm slot. “It’s what feels comfortable to me,” he said. His long extension “also has kind of come naturally.” It creates a physicality that he said improves his ball flight and command.

Sullivan is from Andover, Mass., which is about 25 miles north of Boston. Since age 12 or 13, he has worked with Tom Landry, a pitching coach in Lowell, Mass., which is not far from Andover. Sullivan still makes a point of seeing Landry on his visits home and did so during this offseason. Sullivan said his sessions with Landry are a way to tune up, although Landry’s emphasis on proper technique has long been engrained in Sullivan.

“His ideology was just focusing on health and throwing safely,” Sullivan said. “Which is why I think I’ve been very fortunate, and knock on wood, I haven’t had any serious injuries.

“I think (it’s a matter of) prioritizing not just throwing 100 miles an hour but also make sure you’re throwing the right way and not putting stress on certain parts of your body where it shouldn’t be.”

Sullivan began his college career at Northwestern, which he chose over Virginia Tech. He said he never would have contemplated leaving Northwestern after one year had the coaching staff not been let go.

“I kind of just entered the (transfer) portal for security, just in case,” Sullivan said. “If I wanted to leave and go to another school, it was going to be because I want to get better. Wake Forest has a great track record of just developing pitchers specifically. I really just wanted to get the best version of myself.”

Wake Forest has a renowned pitching lab, an enticement for Sullivan. His phone conversations with Wake Forest head coach Tom Walker and assistant coach Corey Muscara, who works directly with the pitching staff, and pitching lab coordinator Mike McFerran gave Sullivan a greater appreciation for their ability to develop players and the understanding “there is kind of a method to it.”

In 2022 at Northwestern, Sullivan went 5–2 with a 4.45 ERA and an average of 10.9 strikeouts, with 3.5 walks and 9.2 hits allowed per nine innings. He was markedly improved at Wake Forest last year, going 5–3 with a 2.45 ERA. Sullivan averaged 14.3 strikeouts and allowed 2.7 walks and 5.6 hits per nine innings.

At Northwestern, Sullivan “would just throw fastballs over the plate and try to throw strikes and would just kind of get swing and misses. And I didn’t know why, but I’d take them.”

“When I got to Wake,” he added, “they kind of broke (things) down and really showed me the data and like the spots where my fastball plays better or worse, the ball flight on my fastball, and why I get certain swing and misses in this part of the zone but not here.”

While his atypical fastball is Sullivan’s signature pitch, he will need more than that to succeed as a starter. He also throws a slider and changeup.

“Basically, he’s carried by the fastball, and he’s pinpoint with his command,” Rockies Assistant Director of Player Development Jesse Stender said. “And he lives up in the zone. And you just hope that the secondary (pitches) continue to develop, and the secondary (pitches) can play off the fastball.”

The slider, Wallace said, is “a little bit more sweepy than the tight slider.” From his arm slot, the pitch plays well off his fastball. Because he pitches up in the zone, Sullivan’s slider doesn’t need to have major depth, doesn’t need to be a two-plane weapon that takes aim at the back foot of a right-handed hitter.

“He needs it to be one that just keeps extending to his glove side (or in to a right-handed hitter),” Wallace said. “That’s better for him, because from his arm slot, he’s not going to have enough depth to make it get deep enough to get under barrels.”

Sullivan said his slider has improved quite a bit this offseason. He has been trying to make it a little firmer and shorten up the movement.

“I think I have an issue of trying to make it move too much,” he said. “And I think when I kind of just let the grip do the work and just keep the same arm speed, I think it honestly moves a little bit better. It’s a little bit sharper, and it’s a little bit firmer. So I think kind of just focusing on that and I think not trying to make it move too much and just really letting the pitch kind of work itself, that’s going to help me a lot.”

Too much movement made the slider hard to control and made it not a very competitive pitch. Hitters could see it more readily out of Sullivan’s hand, tell it was going to move a lot and just take it.

“I don’t think the command was as good as it could’ve been,” he said. “And I think just not being able to spot it up when I want to wasn’t something very beneficial. So I think that’s something I worked on a lot.”

Wallace said Sullivan has “a feel” for a changeup, although his fastball and slider are going to be his main offerings. As Sullivan has more extended outings and faces a lineup two or three times, he’ll have more need for his changeup.

Sullivan said developing his changeup “a little bit more was like kind of my goal for this offseason.” He said he has seen “a lot” of improvement. Last year, Sullivan said he would slow his arm down somewhat, enough to make it obvious to the hitter that he was trying to throw a changeup. The end result was a pitch that was just a bit slower than his others but not very effective.

“I don’t think it moved very well,” Sullivan said. “But now I changed my grip a little bit where I feel it has more of like that fading (action), more of almost like a two-seam sinker but obviously a little bit slower action to it, which is what I was looking for.”

Sullivan knows he gives the hitters a very different look and has what he called “a good little combo.” One that gives him deception and results from his unusually long extension and low release height, resulting in a different approach to the strike zone than is typical and allowing him to baffle hitters with fastballs up and with ride or movement in on righties.

“I think when a ball is coming from a direction where you’re just not used to it, from an angle at a different approach, it’s just like something that you can’t practice (against).” Sullivan said. “It’s just something different. It’s obviously hard (for hitters) to get (proper) timing.

“I see a lot of swings underneath my fastball just due to like the carry and kind of that deceptiveness that plays on the hitters’ eyes.”

Most pitchers these days throw harder than Sullivan. But lesser velocity hasn’t kept him from sharing a basic pitching pleasure with his mound brethren and sneering, at least inwardly, toward home plate.

“It’s obviously a good feeling,” Sullivan said, “just throwing a bunch of fastballs by guys.”


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