Javier Mascherano has been cleared to play for Liverpool this season after the Premier League accepted the club's request to register him at Anfield.
Mascherano has played for West Ham and Corinthians since July
The Argentine midfielder, 22, agreed to join the Reds before the close of the transfer window last month.
The deal was held up as the Premier League wanted to assess whether the relationship between club and player was "subject to third-party influence".
But the Premier League is now satisfied the move does not breach its rules.
Mascherano flew out with the Liverpool squad for their Champions League tie with Barcelona on Wednesday and is eligible to play against the European champions.
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A statement on the Premier League's website read: "The Premier League has confirmed that the application by Liverpool FC to register Javier Mascherano as a player has been accepted.
"The Premier League is satisfied that the contractual arrangements proposed by Liverpool FC are consistent with its rules; particularly that the relationship between club and player is not subject to third-party influence.
"The Premier League is grateful for Liverpool FC's cooperation and openness at the start and throughout the process."
He is an Argentine international with plenty of experience, so I have every confidence in him
Fifa granted dispensation for Mascherano to make the move at the start of the month, despite the fact he has already played for two clubs since 1 July last year - Corinthians and West Ham.
Under Fifa rules, a footballer cannot play competitively for more than two different clubs between 1 July and 30 June the following year.
However, dispensation was granted after Fifa took into consideration the fact that the South American and European seasons overlap.
And manager Rafael Benitez says he will have no qualms about playing the midfielder as early as Wednesday's Champions League tie against Barcelona.
"He is a very experienced player and is ready," he said. "He is an Argentine international with plenty of experience, so I have every confidence in him."