Sir Alex Ferguson is hoping Manchester United defender Rio Ferdinand has not broken any ribs in the 1-0 win over Arsenal.
Ferdinand was forced off during the closing stages of the first leg of the UEFA Champions League semi-final at Old Trafford on Wednesday night.
The centre-half appeared to suffer the injury after being clattered by Edwin van der Sar as the United keeper came out for a free-kick.
The England international was taken from Old Trafford in an ambulance to undergo further tests on the extent of the injury.
United boss Ferguson admits that, if X-rays show any broken ribs, then Ferdinand is likely to be sidelined for several weeks.
"He's got a crack right on the ribs," Ferguson told Sky Sports. "It's just precautionary and, obviously, we hope it's nothing broken because if you get a rib injury then he'd be out for two or three weeks.
"We will have to wait and see, and we just have to wait on the results."