clock menu more-arrow no yes
@NUCatsBaseball on Twitter.

“He’s got a chance to be a really good one”: Northwestern’s Sean Sullivan is just scratching the surface

After little initial collegiate interest and a viral homemade pitching video, the lefty first-year’s work ethic, skill and mentality have coaches buzzing about long-term stardom.

When Sean Sullivan first ventured from his native Andover, Mass. to Evanston, Ill. last fall, the first-year pitcher knew he would have to adjust: to college life, to new teammates, and to a city over 1,000 miles away from his hometown.

Entering his first season at Northwestern, though, Sean figured he might not have to change his game plan too radically — that is, until his first scrimmage against his new teammates left him stunned.

“There [were] balls hit all over the field,” he said. “I almost thought it was gonna be a little bit easier.”

Fast forward nearly eight months, and it’s safe to say the neophyte experienced a full-fledged metamorphosis.

Leading the Wildcats in strikeouts (78) and averaging 1.41 walks and hits per innings pitched (WHIP) with a 4.45 season ERA, the southpaw has taken a chance to make his mark on Northwestern’s pitching staff by the reins.

In just his second collegiate start, Sean was the magic potion the Wildcats desperately needed after beginning the season 0-5. Out west in Santa Clara, Calif., the 6-foot-3 pitcher went six innings, giving up just five hits and no runs while striking out nine batters. The performance didn’t just give NU its first victory of the year; it allowed Sean to earn Big Ten Freshman of the Week Honors.

Looking back at that Feb. 26 appearance, it’s clear Sean blazed the path toward the ‘Cats climbing out of a 2-10 hole. Yet, his road to Rocky and Berenice Miller Park hasn’t exactly followed a linear pattern similar to the tail of his high-velocity fastball.


In spring and summer of 2020, the COVID-19 pandemic altered every facet of everyday life. High school athletics, especially college recruiting, were particularly impacted by the international shutdown.

Beforehand, Sean had received just one collegiate offer to Tufts University, located in nearby Medford, Mass. at the Division III level. The lack of attention from larger programs left Sean pondering his ability to proliferate his baseball career.

“I’ve been dreaming about it since I was a kid,” he said. “I was like, ‘Oh, it might not happen. Why does nobody want me?’”

Photo provided by Joe Sullivan.

A natural lefty, Sean began playing t-ball around age 6. Despite dabbling at catcher, his dad, Joe, immediately recognized Sean was a perfect fit to pitch.

However, with little college interest and an inability for scouts to travel, Sean’s baseball career hung in the balance. That’s when the father-son duo sprung into action.

Joe built a MacGyver-esque setup, affixing an iPhone to a workbench to film Sean throwing into a net with an adjacent pocket radar. Trying to boost Sean’s stock, the Sullivans shared the video with college representatives — it especially caught the keen eye of Matt Antonelli, Sean’s AAU coach since he was 13.

After viewing the clip of Sullivan hurling at newfound speed in flip flops, Antonelli remembers saying he had never seen Sean do that.

It turns out the video was just the beginning of a meteoric rise for the teenager. Antonelli said he knew Sean would pitch at the college level as early as age 16, but he felt more work was needed in order to make a prototypical jump.

After improving his strength during a four-month span in 2020, Sean returned to Antonelli Baseball, his AAU team. One pitch in, and all Antonelli — himself the 17th overall pick in the 2006 MLB Draft and a former No. 27 overall prospect in baseball — and pitching coach Bryan Menduke could say was “woah.”

When Sean threw a bullpen two months after that, the lefty 17U’s velocity had jumped from 81 to 83 mph to the high 80s.

“We said, ‘Holy crap, he’s going to be dominant,’” Antonelli said. “We were like, ‘He might be able to go wherever he wants to go. He’s gonna be that good.’”

Photo courtesy Joe Sullivan.

Antonelli and his team filmed Sean’s awe-inspiring bullpen and offers flew in like never before.

“Literally every school we sent it to basically either offered him a scholarship or said, ‘We’re going to offer him a scholarship; we just need to see him throw on video in a live game,’” Antonelli said.

After distributing his impromptu backyard session, Sean said he received 15 to 20 offers within a week alone. Of course, one of the schools to enter the mix was Northwestern; the Wildcats targeted Sean in June 2020, and the school quickly emerged as a top choice due to its combination of high-echelon athletics and academics.

Having received heaping amounts of attention, Sean’s baseball career started to crystallize.


From his high school freshman to junior seasons, Sean pitched at local Andover High School. However, after being on the cusp between junior varsity and varsity during that junior season, Sean and his family began to look into preparatory schools.

The Sullivans ultimately settled on Tabor Academy, a boarding school in Marion, Mass. Sean enrolled in the fall of 2019 as a junior, a decision allowed by Sean’s July birthday. Joe believes the choice to repeat grades proved instrumental.

“We knew academically and personally, he needed to mature, develop and grow,” Joe said.

Visions of Sean hurling for the Seawolves were put on hold due to the emergence of the pandemic his first season. However, his full-fledged debut with Tabor the next year did not disappoint.

Photo via Joe Sullivan.

In a condensed 2021 season, Sean made five appearances, including three starts. He accrued 27 innings pitched, striking out 56 while walking just three and giving up one earned run — good for a 0.259 ERA.

One moment stands out to Tabor head coach Kenneth Ackerman above the rest, though.

In a matchup against Noble and Greenough School, Tabor had taken the lead in the top of the ninth of a back-and-forth game. Even though Sean was slated to pitch the next game of the series, he demanded the ball to close the game.

With the save on the line, Sean dominated, earning two three-pitch strikeouts and inducing a groundout on just his seventh pitch.

He went on to bulldoze through the opposition in his start just a few hours later. By the time the seventh inning rolled around, the southpaw had 80 to 90 pitches, yet he refused to leave the mound.

“He goes, ‘Coach, you’re not taking me out of this game,’” Ackerman said. “I’m like, ‘It’s all yours, buddy. Go get it.’”

Sean went and got it indeed, holding Nobles to a shutout over nine innings as Tabor won on a walk-off. Such performances are why Ackerman views Sean so highly among his Independent School League counterparts, calling him “the best of the best.”

Now in his 10th season coaching Tabor Baseball, Ackerman has worked with no shortage of aces, including Jared Shuster — the No. 25 overall pick in 2020 currently with the Double-A Mississippi Braves — and P.J. Poulin — on the Rockies’ Double-A affiliate Hartford Yard Goats. In fact, Ackerman said Sean was “even more dominant” than Shuster.

“I don’t know if Northwestern really knew what they were getting,” Ackerman said.


When Sean got to Evanston in the fall, Northwestern’s coaching staff didn’t have expectations, due to both coaching philosophy and Sean having only pitched a handful of innings in the last few years.

“We didn’t want to say, ‘Hey, you’re a starter [or] you’re a bullpen guy,’” Northwestern head coach Josh Reynolds said.

Photo from Joe Sullivan.

Sean, too, kept a blank slate, but he recognized a chance to earn appearances given Reynolds’ smaller pitching staff.

Entering 2022, senior Mike Doherty was expected to be the Wildcats’ top arm. The year prior, the righty led NU in ERA (3.69) and WHIP (1.25), making 11 starts and giving up just three homers all year. Such numbers had MLB scouts watching intently.

However, Doherty did not experience initial expected results. In Northwestern’s first game of the year, he gave up five earned runs across 5.1 innings, striking out just two. In his following start against Santa Clara, he yielded 10 runs, nine of them earned, in just four frames. After pitching on March 4 at Cincinnati, Doherty battled injury, missing a total of six weeks across March and April.

Despite not reaching desired outcomes, Doherty’s prowess rubbed off on Sean and the senior from Massachusetts became a “huge role model” for the newcomer.

It didn’t take long for Sean to internalize Doherty’s advice. In his first 10 collegiate starts, Sullivan gave up no more than three runs.

Arguably no outing was better than the first year’s day against St. Thomas on March 13 on Opening Day from Rocky and Berenice Miller Park. In seven innings, he tossed a complete game, giving up three hits and no runs with 11 strikeouts and one walk. The performance earned Sean Big Ten Pitcher of the Week.

With his young lefty quickly emerging as a formidable force, Reynolds swiftly rewarded Sean’s efforts. Starting on March 13, the first-year became Northwestern’s “Friday” pitcher, opening every series as the Wildcats’ most intimidating starter. Despite pitching in what most would figure to be the ace’s slot, Sean doesn’t consider himself a bonafide number one.

“Just because I’m starting Friday nights, that doesn’t mean I’m necessarily the ace every weekend,” he said. “I think we have three or four aces on our team.”

Sean’s modesty is something his coaches admire, indicating the mark of a pitcher years ahead of his peers.

“The ones who are the humblest I always feel are the ones that have the greatest shot. And he fits that bill,” Ackerman said.

In a similar vein, Sean’s coaches laud his work ethic and never-ending drive to excel.

“He’s a kid that’s always probably had a lot of success, yet he’s never happy with just being successful. He wants to be a great player,” Antonelli said. “I think it’s what has served him so well and will continue to as he gets older.”

Off the mound, Sean is more demure; Joe describes his son as having a “quiet confidence.” But when he spikes grip the rubber, a different beast is unleashed.

“He’s a bulldog when he’s out there,” Ackerman said. “He’s gonna keep his mouth shut and do his job. And then when you give him the ball, he’s gonna go out there and try and rip your head off. It’s a special thing when you can find that.”

As April Fools’ Day rolled around, Sean’s game plan proved to be no joke. As the ‘Cats began Big Ten play, the first-year held Indiana scoreless through six innings and gave up just three earned runs in five innings to beat Penn State. Then, on April 23, he dominated the Michigan State Spartans, allowing four hits and one run over 7.2 innings en route to a victory.

Maybe the most impressive aspect of Sean’s craft is his ability to rebound. After the shortest start of his collegiate career so far — just 2.2 innings — against No. 15 Maryland, he returned to Miller Park to open a pivotal three-game set with the Ohio State Buckeyes.

The left-hander struggled to throw first-pitch strikes, but Sean fought, retiring his final five batters faced to hold OSU to four earned runs through five frames. Such high-stress scenarios are what Reynolds hopes can truly mold his first-year starter.

“Every time he gets the ball and throws a pitch, it’s gonna be experience he’s gonna get that he’s never had before,” Reynolds said.


With Sean and fellow starter Michael Farinelli carrying the pitching freight, in conjunction with a high-octane offense powered by Ethan O’Donnell, Anthony Calarco and Jay Beshears, the Wildcats clawed out of a 2-10 abyss, reaching 19-16 to sit firmly in sixth in the Big Ten standings. But, following a sweep by Ohio State, a series loss to Purdue and a defeat by Notre Dame, Northwestern now sits at 22-26, its 8-13 conference record placing the team ninth in the Big Ten and on the outside looking in at the conference tournament.

The Wildcats have shown a knack for late-game comebacks all year, and they might have just one more in store if they handle business in Minneapolis against the Minnesota Golden Gophers. Regardless of the ultimate outcome of the 2022 season, Sullivan’s future has many thrilled.

Photo from @NUCatsBaseball.

His emerging success at the Big Ten level continues to impress his former coaches. While Sean’s long fingers amaze Ackerman, so does his relative inexperience, leading to less wear on the lefty’s arm.

“I think the most important part of him is he’s not this kid who’s been groomed since he was 9 years old [to] go out and throw too many pitches,” Ackerman said. “I think the sky’s the limit with him. Somebody’s gonna like him early in the early rounds in a couple of years.”

For as much as Reynolds does not enjoy imposing expectations, his words speak volumes about Sullivan’s potential.

“As that [throwing more offspeed pitches] progresses in his development, then he’s gonna continue to get better. He’s got a chance to be a really good one,” Reynolds said.

With a future brighter than Northwestern’s home white jerseys, it could be easy for Sean to become hypnotized by visions of grabbing a freshly printed Major League Baseball jersey with his name on the back. Nevertheless, his attention remains primed on what’s directly in front of him.

“Baseball is one of the highlights of my life, and obviously I’d like to play for as long as possible,” Sean said. “[I] don’t really focus on the path. [I] take each game by game and go out there, work hard, have fun and see where it goes.”

Matt Fitzpatrick, men’s basketball updates and more

Breaking barriers beyond Northwestern: Female alumni with careers in sports

How Title IX helped Northwestern’s first female varsity athletes reach new heights