Sunderland midfielder Lee Cattermole may visit a specialist after aggravating a groin injury.
Cattermole initially sustained the injury during last week’s friendly against Munster and had to limp off during Saturday’s match at Darlington.
Assistant manager Eric Black said: “Lee wanted to try it out but he suffered a recurrence after 10 minutes.
“We may now send him to see a specialist on Monday.”
Cattermole may now be facing a race against time to be ready for the new Premier League campaign, which kicks off on August 14.