Jason McAteer faces a race to be fit for the crucial relegation clash against his former club Bolton.
McAteer is struggling to face his former team
The Irish international suffered a hamstring injury in the Black Cats 1-0 defeat at Fulham, although he finished the game.
Although a scan revealed only minor damage, McAteer will not be able to resume training until the muscle is fully healed.
McAteer featured in Sunderland's last three games after returning from a long-term hernia problem which required two bouts of surgery.
Surgery is definitely an option but then my season is over
McAteer told Sunderland's official website: "I just felt something go early in the game at Fulham.
"The scan has showed some damage to the hamstring but I'm hopeful of being OK for the Bolton game."
With Gavin McCann suspended for the Bolton clash and the trip to fellow strugglers West Ham the following week, McAteer's injury is another midfield concern manager Howard Wilkinson could do without.
To add to Wilkinson's problems, utility man Darren Williams was stretchered out of Sunderland's reserve defeat by Sheffield Wednesday.
Myhre's season has been wrecked by injury
Goalkeeper Thomas Myhre is considering surgery to cure a his long-standing thigh injury.
The Norwegian international accepts that surgery will put an end to a season wrecked by injury problems.
Myhre has played in one Premiership match this campaign and was hoping to move to a First Division club on loan to regain his sharpness but the injury struck again.
Myhre said: "I really just want to forget this season.
"Surgery is definitely an option but then my season is over.
I've had many injuries and it's time to start to take care of my health
"This is not a normal thigh strain. It is obvious that the muscles cannot take the normal workload.
"It's not normal and it worries me that things have gone wrong," Myhre Sunderland's official website.
Myhre's decision to go under the knife would rule him out of Norway's Euro 2004 qualifiers against Luxembourg, later this month, and Denmark in June.
Meanwhile midfielder Stefan Schwarz has announced he will retire at the end of the season.
The 33-year-old Swede has not played in the Premiership for a year and his Sunderland contract expires at the end fo the current campaign.
Schwarz has found his opportunities limited
Schwarz said: "I'm still under contract with Sunderland and will train with the club until the end of the season and then I will probably retire.
"I've had many injuries through the years and it's time to start to take care of my health.
"There's a life after football too," Schwarz told Sunderland's official website.
Schwarz dropped plans to extend his playing career abroad in the wake of medical advice and will now pursue coaching qualifcations.