Sunderland are waiting on the results of tests on goalkeeper Lee Burge after he suffered a heart issue in the wake of his recent positive Covid test.
Burge was on the bench for Sunderland's win against Sheffield Wednesday at the end of December but tested positive for Covid shortly afterwards and has not featured in the matchday squad since.
And Black Cats boss Lee Johnson has revealed that the 29-year-old has had a heart problem which needed to be checked out before he could return to action, with the club expecting the results of blood tests later today.
READ MORE: Sunderland facing 'fluid' injury situation in run-up to Portsmouth clash
"Lee Burge has had to undergo some heart tests," Johnson said.
"He had Covid and on the back of that he has had some heart palpitations.
"I think we're due to get the results back this evening from his blood test.
"I think he's alright, but it was the right thing to do from the point of view of the medical staff just to check that one out."
It is not the first time that a Sunderland player has encountered heart problems following a positive Covid test.
Last season, on-loan Southampton defender Jake Vokins had a similar issue after he had contracted Covid in March and he did not recover in time to play any further part in the campaign.
Both Burge and first-choice keeper Thorben Hoffmann tested positive for Covid at the turn of the year, forcing Sunderland to recall academy graduate Anthony Patterson from his loan spell with Notts County in order to start the games at Wycombe and at home to Lincoln City.
Hoffmann returned for last weekend's trip to Accrington, with Patterson dropping to the bench.
When Patterson was recalled, Sunderland said the plan was to allow him to resume his loan at Notts County later in January.
But Burge's health issue has meant that Patterson's return to Meadow Lane has been put on ice for now, although it is still likely to happen once Burge is available again and because Notts County play in the National League he can join the Magpies outside the transfer window.
Johnson said: "Obviously we hope he [Burge] is alright, but of course that has a domino effect on Anthony Patterson's situation."
Patterson was one of three loan players recalled to help Sunderland continue playing when they were reduced to the bare bones by a combination of Covid and injuries.
Jack Diamond was brought back from Harrogate Town, while Josh Hawkes was recalled from Tranmere Rovers.
The Covid situation at the Academy of Light has now eased, and some of the injured players have returned, which the Black Cats have also added two new signings in Trai Hume and Danny Batth.
Sunderland now have decisions to make over whether to allow Diamond and Hawkes to go back out on loan.
Both Diamond and Hawkes have played for Sunderland this season and the rule that says a player can only represent two clubs in one season mean that they can only be sent back out to Harrogate and Tranmere respectively.
And with Harrogate and Tranmere both competing in League Two, they would have to go out on loan before the transfer deadline passes at the end of January.
Johnson said: "With two or three back in the mix - and potential signings as well - it does give us those decisions to make."
For the latest Sunderland news direct to your inbox, go here to sign up to our free newsletter
