The ink was barely dry on Casemiro's Inter Miami contract before Major League Soccer announced it was investigating the club that signed him.

MLS confirmed this week that it is reviewing a tampering allegation against Inter Miami, the club co-owned and fronted by David Beckham, over the process by which it secured the 34-year-old Brazilian midfielder following his exit from Manchester United.

At issue is MLS's "Discovery" system, a league mechanism designed to stop clubs bidding each other up for unsigned international players by granting one franchise exclusive negotiating rights to a target. According to ESPN and CBS Miami, LA Galaxy — not Inter Miami — originally held those discovery rights to Casemiro.

Inter Miami and Galaxy have since reached a settlement transferring the rights, reportedly worth around £750,000, but MLS has not disclosed whether the tampering concern relates to contact Miami may have had with Casemiro before acquiring those rights, or to the rights transfer itself.

"Major League Soccer is reviewing a tampering allegation against Inter Miami CF," the league said in a statement carried by multiple outlets, adding that it was "gathering all relevant information" and would not comment further until the review concludes.

Both clubs have confirmed an agreement was reached but say the full terms will only be released once the investigation is complete.

Casemiro has signed through the 2027 MLS season with an option to extend to 2029, joining Lionel Messi, Luis Suárez and Sergio Busquets in Miami's high-profile squad. The five-time Champions League winner left Old Trafford as a free agent after five seasons in the Premier League.

It is not the first time Beckham's club has drawn league sanction. In 2021, Inter Miami was fined $2 million by MLS after an investigation found the club had violated salary cap and roster rules connected to the signing of former France international Blaise Matuidi.

No penalty has been imposed over the Casemiro deal at this stage, and MLS has stressed the process is ongoing, but the precedent of the Matuidi case means fines or roster consequences cannot be ruled out if wrongdoing is confirmed.

For now, Casemiro's arrival stands as one of the most eye-catching MLS transfers of the year — even if the circumstances of how Miami cleared him for signing are still being picked apart by the league that will decide whether the deal was done by the book.