Cavan Sullivan Sets MLS Teen Assist Record, Value Hits €10m

Philadelphia Union forward Cavan Sullivan set a Major League Soccer record for assists by a teenager in a single season, reaching 12 assists after his performance against Sporting Kansas City, MLS confirmed on September 20, 2026. The 16-year-old, who turns 17 on September 28, has also become one of the most valuable under-21 players in MLS after a Transfermarkt market value update on September 18 placed him at €10 million, ahead of fellow young Americans Adri Mehmeti and Mbekezeli Mbokazi, who are each valued at €8 million.

Sullivan’s rise comes as he continues to play out the final stretch of the 2026 MLS regular season with Philadelphia Union while a future move to Manchester City, agreed for after his 18th birthday, remains in place but not yet in effect. The player has not left MLS and the Manchester City transfer has not been completed as of September 23, 2026; Sullivan remains contracted to and playing for Philadelphia Union.

Direct Answer: What Happened This Week

MLS credited Sullivan with 12 assists for the 2026 season following his display against Sporting Kansas City in mid-September, a figure the league described as a record for a teenage player in a single MLS season. Separately, Transfermarkt’s September 18 valuation update lifted Sullivan’s market value to €10 million, the highest among under-21 players in MLS in that update, with Mehmeti and Mbokazi close behind at €8 million each. Neither development changes Sullivan’s contract status with Philadelphia Union or the timeline of his already-arranged move to Manchester City.

Record-Breaking Numbers Behind the Headline

The scale of Sullivan’s 2026 campaign has been difficult to track precisely because different outlets and MLS itself have published varying tallies at different points in the season, a common feature of in-season reporting on a player whose production has accelerated rapidly. What is consistent across sources is the direction: Sullivan’s output has climbed sharply in the second half of the season, culminating in the record-setting assist mark confirmed by MLS on September 20.

One September snapshot had Sullivan with 23 MLS appearances and more than 1,200 minutes played this season. A separate stat line from the same period listed 24 MLS appearances with 7 goals and 5 assists. MLS’s own release after the Sporting Kansas City match credited him with 19 regular-season goal contributions in total — 7 goals and 12 assists — which is the figure underpinning the teenage assist record. Another accounting attributed 6 goals and 11 assists to Sullivan on the basis that MLS counts secondary assists, while a competing report described 6 goals and 5 assists over a similar stretch. A wider, all-competitions total from early-to-mid September put him at 9 goals and 15 assists.

The variance reflects different cutoff dates and different definitions of assists (primary versus primary-plus-secondary) rather than a factual dispute. What multiple reports agree on is that Sullivan produced goal contributions in seven consecutive regular-season matches in September, a streak also described as a teenage MLS record, and that his past seven matches at one point yielded nine combined goals and assists.

Sullivan first drew national attention when he made his MLS debut at 14 years and 293 days old, breaking a record previously held by Freddy Adu. Born on September 28, 2009, he turns 17 in five days, meaning the bulk of his record-setting 2026 production has come while he was still 16.

Transfermarkt Valuation: Sullivan Tops MLS Under-21 Rankings

Transfermarkt’s market value tracking is widely used across football media to gauge how a player’s transfer value is trending, and its September 18, 2026 update on MLS’s youngest talents placed Sullivan at €10 million. That figure put him ahead of Adri Mehmeti and Mbekezeli Mbokazi, both valued at €8 million in the same update. Any valuation list published before September 18 is now considered outdated relative to this update.

Transfermarkt’s valuations are not official transfer fees but analyst-driven estimates based on age, performance, contract length and market comparables. They are, however, closely watched by clubs, agents and media as a proxy for a player’s rising or falling stock. Sullivan’s jump to the top of the MLS under-21 list mirrors the on-field numbers: a player who debuted as a 14-year-old curiosity has become, within roughly two years, the most statistically productive teenager in the league.

Mehmeti’s inclusion alongside Sullivan is notable beyond the valuation table. Mehmeti was also named among the players included in a United States national team call-up list in September 2026, placing him alongside Sullivan in the current generation of American teenage prospects drawing international attention.

The Manchester City Move: Agreed, But Not Yet in Effect

Sullivan’s path to Manchester City was arranged in advance of his current MLS breakout, with the transfer structured to take effect around his 18th birthday under MLS’s rules governing international player sales. As of September 23, 2026, that move remains a future transaction — Sullivan has not left Philadelphia Union, no medical or transfer window paperwork has been completed for an immediate switch, and he continues to play MLS matches as a Union player. Nothing in this week’s record-setting statistics or valuation update changes that timeline; the news is about his production and market value now, not a change in his transfer status.

Readers should treat the Manchester City move as previously arranged and still pending, not as new or completed news. The club has not issued a fresh announcement this week altering the terms or timing of that agreement.

USMNT Recognition Adds to the Storyline

Sullivan’s club form has coincided with his emergence in the United States men’s national team picture. Reporting in September 2026 said Sullivan is set to become the USMNT’s fourth-youngest player if capped, a benchmark that would place him among a small group of American teenagers to have played for the senior team. Coverage between September 16 and 20 repeatedly linked his first USMNT call-up to his record-breaking MLS season, framing 2026 as the year his club performance forced a place in the senior international conversation.

That international recognition, layered on top of the MLS assist record and the Transfermarkt valuation jump, has made Sullivan’s file this month unusually dense: a record-breaking domestic season, a rising market value, and imminent senior international involvement, all while a marquee European transfer already sits on the calendar for less than a year from now.

Context: Philadelphia Union’s Development Pipeline

Philadelphia Union has built a reputation in MLS for developing young American talent through its academy system, and Sullivan is the most prominent recent product of that pipeline. His trajectory — academy graduate to record-setting first-team contributor to a pre-arranged move to one of Europe’s wealthiest clubs — reflects a broader trend of MLS academies using the league’s Homegrown Player rules to develop talent that is later sold abroad for significant transfer fees, even when, as in Sullivan’s case, the buying club is prepared to wait for the player to become eligible for an international move.

For Manchester City, the arrangement secures a highly rated attacking prospect years in advance of his arrival, a strategy the club and other major European sides have increasingly used to lock in young talent from growth markets like MLS before prices rise further. Sullivan’s climb to a €10 million valuation while still four days short of his 17th birthday suggests that strategy is already paying off in perceived value, even before he has kicked a ball for the English club.

What to Watch Next

• Whether Sullivan receives an official USMNT call-up and becomes the program’s fourth-youngest capped player.
• Sullivan’s 17th birthday on September 28, 2026, and whether Philadelphia Union’s remaining regular-season fixtures add further goal contributions to his record tally.
• Any further Transfermarkt valuation updates as the MLS season concludes and Sullivan’s move to Manchester City draws closer on the calendar.
• Official confirmation from Manchester City or Philadelphia Union of any change to the previously arranged transfer timeline.

For background on how young attacking talent is valued and tracked across European leagues, see Como’s rise in Serie A’s squad value rankings, another case of a market-value update reshaping how a club’s young talent is perceived. Sullivan’s case also echoes broader patterns covered in explanations of how modern attacking roles are read and valued across competitions.

Limitations of This Report

Statistical totals for Sullivan’s 2026 season vary between sources depending on the reporting date and whether secondary assists are counted, as reflected in the table above. This article has presented each figure with its original attribution rather than reconciling them into a single number that no source actually published. No official Manchester City statement on the transfer’s status was issued this week, and this report does not claim otherwise.

Sources

• market value tracking — transfermarkt.com
• Sullivan, Mehmeti, Mbokazi & Co.: The 10 most valuable U21 MLS stars — transfermarkt.co.uk
• Cavan Sullivan — mlssoccer.com
• Major League Soccer: The most valuable teenagers to watch — transfermarkt.com
• Cavan Sullivan – stats, career and market value – FotMob — fotmob.com

Photo: Bryan Berlin, CC BY-SA 4.0, via Wikimedia Commons