TRANSFER TRACKER STATUS: Transfer
The Union did not release details of the transfer, but sources tell MLSsoccer.com the deal is worth $4 million plus add-ons, plus a "big" sell-on percentage.
Aaronson, 19, made his MLS debut in 2021 and made 37 MLS appearances, where he had four goals in 1,006 minutes. He likely would have earned more minutes if not blocked by 2022 MLS Best XI presented by Continental Tire selection Daniel Gazdag as the Union pushed in the Supporters' Shield race and reached their first MLS Cup final.
“Paxten has accomplished so much in a short amount of time," sporting director Ernst Tanner said in a club statement. "He has worked incredibly hard, and he has taken advantage of every opportunity with the first team, Union II and the U-20 National Team. There has been interest in him for a long time, and we feel this is the right move for the club and the player, putting him in a good situation to continue developing in one the best leagues in the world. It is another great example of our development philosophy, and we are very proud of Paxten and wish him all the best at Frankfurt.”
A US youth international, Aaronson won the Golden Ball and Golden Boot at the U20 Concacaf Championships. Led by Aaronson, the United States won the tournament, qualifying for both the next U20 World Cup and Olympics.
Clubs in Europe have been tracking Aaronson for long before that tournament, a big talent in the eyes of scouts. RB Salzburg, who signed his older brother Brenden Aaronson, were among those with long-term interest, but a deal got done with Frankfurt.
Aaronson will join Frankfurt in January, with no plans of being loaned out. The club sit fourth in the Bundesliga. He's not expected to play a ton with the first team as he gets settled and adapted. The club play with two No. 10s, giving Aaronson further opportunities for minutes in the future.
Other Americans in the Bundesliga include Gio Reyna (Borussia Dortmund), Joe Scally (Borussia Monchengladbach), Jordan Pefok (Union Berlin) and more. MLS clubs have transferred young talents to Germany in recent years, including Kevin Paredes, George Bello, Justin Che and more.
Aaronson becomes the third most-expensive outbound transfer in Union history, behind his brother Brenden and Mark McKenzie. All three transfers have come in the last two years as the club have remade themselves among the elite developmental sides in the league under Tanner and head coach Jim Curtin.
Brenden's deal ended up at $9 million after all incentives hit, plus the club received around another $5 million from their sell-on clause when he was transferred to Leeds United this summer. McKenzie joined Genk for an initial fee around $6 million, with add-ons and a sell-on clause as well.
Standout left back Kai Wagner is expected to be the next opulent transfer from Philly, while European teams have interest in Jack McGlynn, Quinn Sullivan, Olivier Mbaizo and others as the pipeline won't slow down anytime soon.
READ MORE: MLS Transfer Tracker presented by Avant