Is Cavan Sullivan the Next Big Thing in MLS?

A Historic Start in Nashville

On July 5, 2025, Philadelphia Union unleashed their teenage prodigy Cavan Sullivan for his first MLS start against a red-hot Nashville SC, riding a 14-game unbeaten streak. At 15 years and 280 days, Sullivan became the second-youngest player to start an MLS match, just behind Freddy Adu’s 2004 record of 14 years and 334 days. Playing 60 minutes before subbing off for Ben Bender in a scoreless tie, Sullivan completed three of five passes but couldn’t stop a late Hany Mukhtar penalty from sealing a 1-0 defeat for the Union.

Union coach Bradley Carnell deployed Sullivan as a wingback, leaning on his knack for counterpressing to spark transitions. “He got one or two looks in the first half where we could start creating something,” Carnell noted postgame. But the teenager’s inexperience showed—he was muscled off the ball and earned his first career yellow card after halftime, a classic MLS baptism.

“Sullivan’s got the talent, but he’s still a kid in a man’s game,” a GEODIS Park observer quipped, eyeing the scoreboard.

Building on a Record-Breaking Path

Sullivan’s no stranger to making history. A year ago, at 14 years and 293 days, he became the youngest MLS debutant ever, surpassing Adu’s mark. His start against Nashville, a fortress unbeaten in league play since March, was a bold test. As a wingback, Sullivan’s high-energy pressing shone, but his slight frame struggled against Nashville’s physicality, a gap Carnell called “totally natural” for a 15-year-old.

The loss pushed Philadelphia from first to third in the Eastern Conference, two points behind FC Cincinnati in the Supporters’ Shield race. Yet Sullivan’s cameo, though without a goal or assist, offered glimpses of his potential—a quick turn, a sharp press—that explain why he’s the Union’s prized prospect.

“He’s not Adu 2.0—he’s Sullivan 1.0, and that’s enough to get excited,” a Union fan posted on X, half-hopeful, half-hyped.

Managing the Hype Machine

Sullivan’s start wasn’t just a game; it was a media frenzy. MLS thrives on prodigies, and Sullivan’s age, skill, and poise make him prime headline fodder. But Carnell’s postgame remarks were measured: “We need to progress him without putting him under pressure. He’s performing right where he needs to be”. The subtext? The hype around Sullivan could overwhelm him if not carefully managed.

Physically, he’s not ready for MLS’s grind—his three-of-five pass completion rate shows he’s still finding his footing. Mentally, though, his relentless pressing and fearlessness hint at a maturity beyond his years. The Union’s challenge is nurturing his growth while chasing trophies, especially with upcoming clashes against rivals New York Red Bulls in the US Open Cup quarterfinals on July 9 and in league play on July 12.

“Sullivan’s a diamond, but you don’t polish one by throwing it into a grinder,” a soccer analyst muttered, scrolling through stats.

The Road to Stardom

Sullivan’s next target—a first MLS goal or assist—is tantalizingly close. The back-to-back Red Bulls matchups offer a stage for a breakout moment, with Union fans dreaming of their teenager stealing the show against a hated rival. Nashville’s physicality was a reality check, though: Sullivan needs time to build strength and sharpen his game to survive MLS’s demands.

With Philadelphia third in a tight Eastern Conference, leaning too heavily on Sullivan risks stunting his growth. Carnell’s plan is clear: ease him in, letting his flair shine in big moments like the Red Bulls games. A goal or assist would ignite Philadelphia’s fanbase, cementing Sullivan as a homegrown hero. If it doesn’t come, his upward trajectory still holds, as long as the hype doesn’t crush him.

Sullivan’s debut is a snapshot of MLS’s future, where young talents can shatter records and spark hope. But at 15, he’s navigating a league that’s as brutal as it is thrilling. The Union and their fans must temper their excitement with patience to let this star rise without burning out.