Sunderland have signed Boavista goalkeeper Mika on a two-year deal for an undisclosed fee.
The 25-year-old could make his Premier League debut against Everton on Monday.
Fifa have ratified the signing after a technical issue meant Boavista were unable to complete their requirements by the 23:00 BST deadline on 31 August.
Sunderland needed cover in goal after first choice Vito Mannone, 28, was ruled out for up to three months with an elbow injury.
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