The move
To sign Arfsten , Middlesbrough will pay the Crew a fee of up to $7.5 million, sources tell GOAL, with that fee also including add-ons and bonuses. The Crew, meanwhile, are set to retain a sell-on clause.
Boro had been after Arfsten for a while before getting the deal over the line. The club pursued the 25-year-old defender/winger last summer, while French side Toulouse also made a bid to sign Arfsten in 2025.
"I'm very excited to be here and want to do everything I can to make this fanbase proud," Arfsten said in a statement. "When I heard about the ambitions of the club, how they are as people and the direction the club is going in, it intrigued me.
"I've been wanting to come here for some time, and now I just can't wait to train with the team and hit the ground running."
American links
Arfsten has become the third USMNT player in the Middlesbrough squad, all of whom have ties to Columbus.
Morris joined the club in 2024 and has become one of Boro's most important pieces, helping lead the team to the promotion playoff last season. They ultimately fell short in the final, ensuring their stay in the Championship this season.
To continue their pursuit of a Premier League spot, the club recently went out and signed Berhalter from the Vancouver Whitecaps . Berhalter's deal was set to expire in the winter, but Boro were able to secure his services this summer for a fee of around $2 million.
"Aidan especially has been telling me about the style of play, the culture of the club and the fanbase here," Arfsten said. "Having both Aidan and Seb here will make the transition easier, because it's always a big deal signing for a new club.
"I'm just excited to have a new challenge, and I'm looking forward to getting going."
Arfsten's career so far
Arfsten has developed into one of the best wingbacks in MLS in recent years, earning All-Star selections in each of the last two summers. Originally drafted by the Crew in the 2023 MLS Draft, Arfsten's rise saw him make his USMNT debut in 2025. He has since made 21 appearances and was a member of the team's World Cup roster. He played in one game at this summer's tournament, coming off the bench against Belgium .
Boro will begin competitive fixtures with an EFL Cup match against Wrexham on Aug. 7 before the Championship season begins on Aug. 15 against Lincoln City.
