West Brom manager Tony Mowbray is hopeful that James Morrison's injury is not as bad as first feared.
The midfielder was forced to withdraw from the Scotland squad for the friendly against Argentina at Hampden Park on Wednesday.
The former Middlesbrough man suffered medial ligament damage in Saturday's 3-0 loss to league leaders Chelsea and Mowbray has his fingers crossed.
He told West Brom's official website: "James has tweaked his medial knee ligament. Hopefully it's not too bad.
"These injuries come in various grades and we're not sure how bad it is at the moment.
"The worst-case scenario is that he's shook it up and it settles down in a few days. We'll know more when he's back from Scotland.
"We'll do our own diagnosis on him. Sometimes, it's very difficult to assess an injury straight after a game due to the bruising and tenderness of it.
"Fingers crossed it's not too bad."
Mowbray also explained that he took off defender Abdoulaye Meite as a precaution after the former Bolton man had just returned from an 11-week lay-off.
He added: "Abou had only had one weeks' training. The game was finished and there was no point in risking his calf, which can be affected by fatigue."