Norwich striker James Vaughan will undergo a scan to determine the extent of his latest injury blow.
The former Everton man limped out of the Canaries' 2-1 win over Sunderland on Monday, having only been on the field 10 minutes as a substitute.
Vaughan has had plastic surgery on a lip injury already this term and missed the beginning of the season with a knee complaint, but club boss Paul Lambert confirming the latest setback is a fresh concern.
"He's just came back from a knee injury, the only thing is it's not the same one as he hurt before, we'll have to wait and see," Lambert said.
"His knee is locked which is not a good sign, we'll know more on Tuesday. He's really unlucky and is a bit down as you can imagine."
Vaughan, 23, had knee surgery on two occasions in his Everton days, while a severed artery and dislocated shoulder rank high among the worst setbacks of the striker's injury-hit career.