Aston Villa boss Martin O'Neill has challenged goalkeeper Stuart Taylor to make the most of his chance and put the pressure on Thomas Sorensen.
Sorensen faces three weeks on the sidelines after colliding with Middlesbrough defender Emmanuel Pogatetz in Saturday's 1-1 draw, and will undergo an exploratory operation to see if there is any damage to the cartilage.
"Thomas has got a problem with his knee," O'Neill told Sky Sports News.
"He came off on Saturday and he will get a scope (arthroscopy) tomorrow and if there is any other damage underneath we should be able to get something sorted, but he'll be out for a few games."
Former Arsenal goalkeeper Stuart Taylor came on for the last 20 minutes against Boro and O'Neill believes he will prove to be a more than able deputy against Manchester City on Wednesday.
"Stuart has played a number of games for us this season, so it's not as if this is his first game," he said.
"I thought that his 20-odd minutes on Saturday were particularly testing.
"I thought his handling was pretty good, he's got plenty of confidence now about himself and I'm sure he's ready now to step up and be the goalkeeper everyone at Arsenal thought he was going to be a couple of seasons ago."
And O'Neill wants Taylor to believe he can take over from Sorensen as Villa No.1
"That should be in his mentality. I don't think there's any point hanging around a football club if you're going to play second fiddle to people," he urged.
"I do accept that the goalkeeping position is a wee bit different. Sometimes you can be a top quality goalkeeper and sit out for a couple of seasons because the feller you're trying to displace is absolutely fantastic.
"But every chance that you get is a chance you should take."