Hleb left St. Andrew's on crutches after being on the receiving end of a mis-timed challenged from Owls defender James O'Connor.

The former Arsenal player will have a scan in the next 24 hours which will determine whether he can recover in time to face the Gunners at Wembley next weekend.

Blues boss Alex McLeish said: "The latest is Alex is limping heavily. He will have a scan hopefully over the next 24 hours.

"We presume we can get something done tomorrow and we will know after that if there is any damage.

"It is his knee. We don't believe there is any cruciate problems but he got a fair rattle. The guy was very late in the tackle.

"He is a great player and we still believe he will make an impact for us at some stage this season and, hopefully, he will be okay for the final."

McLeish admitted he also substituted key defender Roger Johnson over fears he would be sent off and so banned for the final after he had collected a yellow card.

He said: "I thought 'one mis-timed tackle from Roger and he is looking at red with disastrous consequences'.

"It was a good opportunity to take Roger off. If the scoreline had been tighter, we would have gone along with him. I felt it was the right thing to do."

Striker Cameron Jerome was substituted at half-time with an ankle injury although he should be fit for the final.

McLeish was pleased with his side's performance after making eight changes.

He said: "In terms of allowing players to recharge batteries and being able to change the team, and also for the players to come in and get some much-needed match practice, it was a good day for us."

Owls boss Gary Megson was livid with the standard of his side's defending.

He said: "It was terrific for us for the first six minutes and yet again, each time the opposition have their first attack they score from it.

"Woeful doesn't describe it adequately, the simplicity of the goals against us.

"It shouldn't happen like that. If someone scores a world-class goal against you, or a lucky one, there is not a huge amount you can do.

"But the first goal is an awful one to give away. It starts on the halfway line and is a ball we should clear and be a lot stronger with.

"Next time we are touching the ball, it is in the back of the net. The second goal is even worse."

Goals from Jean Beausejour, Obafemi Martins and David Murphy sealed a quarter-final spot for Blues.