Sunderland has appealed to Fifa in the hope of gaining a transfer deadline exemption to sign Mika, the Boavista goalkeeper, outside the transfer window.
David Moyes’s first choice keeper Vito Mannone was ruled out for months with an elbow injury.
Second-choice Jordan Pickford also suffered from a thigh problem as he withdraws from England Under-21 duty.
The injuries meant that Sunderland is without a fit senior goalkeeper.
Earlier, an agreement has been reached over Mika’s transfer from Portugal shortly before Wednesday night’s transfer deadline but a delay in finalising the paperwork at Boavista’s end dictated the move fell through.
Although Pickford is expected to recover in time for Sunderland’s home game against Everton, the club is deeply in want of their appeal to succeed.
Should it fall through, the Black Cats will resort to requesting permission for an emergency loan from the Premier League.
Premier League clubs without two senior goalkeepers are permitted to seek this sort of cover on a week-by-week basis, while such short-term deals have now been abolished for outfield players.