MLS has determined that when Matuidi, 34, joined from Juventus last August he should have been classified as a Designated Player on the roster due to the size of his salary.
Instead, Inter Miami listed him as a Targeted Allocation Money (TAM) player, allowing them to use their three designated player slots for Gonzalo Higuain, Rodolfo Pizarro and Matias Pellegrini.
The designated player rule – under which certain players’ wages do not count towards the salary cap – was first introduced to facilitate Beckham’s move from Real Madrid to the LA Galaxy in 2007.
An MLS statement said: “The league has concluded that Inter Miami was not in compliance with the roster and budget rules during 2020.
“In 2020, Matuidi was categorized as a Targeted Allocation Money (TAM) player. Matuidi’s compensation was above the compensation limit for a TAM player and he should have been classified as a Designated Player.
“As a result, Inter Miami CF violated the Designated Player Limit as the team had three Designated Players in addition to Matuidi during 2020.”
The league said it was still finalising its investigation and will make a full announcement, including sanctions, shortly.
In response to the ruling, Inter Miami have completed a buyout of Pellegrini’s contract and sent the 21-year-old on loan to their USL affiliate Fort Lauderdale for the season. The Argentinian will not be eligible to play for Phil Neville’s side during the 2021 campaign.
“We’ve been working with Matias, his representatives and MLS to reach an agreement, and at this time we believe this is the best option for all parties,” Inter Miami sporting director Chris Henderson said.
Beckham is the co-owner of Inter Miami and president of soccer operations. In their debut campaign they finished 10th in the Eastern Conference, losing to Nashville in the first round of the play-offs under former head coach Diego Alonso.
Former England Women’s coach Neville was appointed in January, and his side will begin their 2021 season against the Galaxy on Sunday