David Beckham's Inter Miami are under investigation by Major League Soccer over alleged tampering following the club's signing of Casemiro.
The Brazilian midfielder was unveiled Wednesday after agreeing to an initial contract through 2027, with an option to extend his stay until June 2029. The transfer remains subject to visa approval.
Shortly after announcing the deal, MLS confirmed it had opened an investigation into the reigning MLS champions.
In a statement, the league said: "Major League Soccer is reviewing a tampering allegation against Inter Miami CF. The league is gathering all relevant information and will refrain from further comment until the review is complete.
"While Inter Miami CF and the LA Galaxy have reached a settlement for the discovery priority to sign Casemiro, the terms will be released upon conclusion of the tampering investigation."
MLS has a rule known as the discovery process, under which clubs may place up to five players on their discovery list, giving them priority rights to negotiate with those players.
Casemiro, the 34-year-old former Real Madrid and Manchester United midfielder, was on the LA Galaxy's discovery list.
However, the Brazil international, who became a free agent after his contract at Manchester United expired at the end of last season, chose to sign with Lionel Messi's Inter Miami.
The LA Galaxy said in a statement: "The LA Galaxy and Inter Miami CF have reached a settlement for the discovery priority to sign Casemiro, and the terms will be released upon conclusion of the tampering investigation currently open with Major League Soccer."
Casemiro won five UEFA Champions League titles during his time with Real Madrid before lifting the League Cup and FA Cup with Manchester United.
He told Inter Miami's official website: "What motivates me the most, and I think this is true for every player, is winning and continuing to grow. The project the club presented to me, along with the effort everyone made to bring me here, means a lot to me.
"I'm incredibly grateful, and I can't wait to get started so I can repay that trust, not only during the 90 minutes on matchday but every day in training as well.
"All I can say is thank you, and I'll give everything I have to return the affection and confidence the club has shown me."
Capped 91 times by Brazil, most recently in the World Cup round of 16, the former Sao Paulo player brings vast experience to his new club.
Inter Miami co-owner Beckham said: "I'm very proud to welcome Casemiro and his family to Inter Miami. He is a person and a player that I have admired for a long time.
"He is a winner who has achieved so much in the game, and after such an incredible career with Real Madrid and Manchester United, I'm delighted that he's decided to make Miami his next home."
