Sunderland's Premier League battle is threatening their deal for Hearts of Oak striker Mahatma Otoo.
Sunderland have been recommended Otoo by their African contacts and he was expected to be handed trials.
But with the club fighting relegation, all transfer talk has been put on-hold, so opening the door to Benfica to swoop for the Ghana international.
Hearts of Oak officials have confirmed the interest of Benfica, though as yet no concrete offer has arrived for the striker.