Aston Villa boss Martin O'Neill admits Gareth Barry could cause problems on his return to his former club.
Barry left Villa for Manchester City in the summer and has flourished at Eastlands so far this season.
Returning to the club he spent 12 years with from trainee level on Monday, the England international will be hoping to bag a goal against his former team-mates to add to his two in City's last three games.
Knowing full well the threat his former player poses, O'Neill admitted to having mixed emotions in anticipation for Saturday's game.
Return"He's been a good player here. A very good player. He was here for a long, long time," O'Neill told Sky Sports News.
"He would have to come back sometime, obviously.
"But instead of playing for us he's playing against us and that in itself will make life difficult for us.
"We'll try and deal with it accordingly. He's playing in a team at the minute that are absolutely flying.
"It's going to be a really tough game for us, but it's obviously one we are looking forward to."
DecisionAsked if he regrets selling Barry, O'Neill said: "He's given a lot of service to the football club, which is important.
"But he chose to leave in the end. I accepted his decision, that was what he wanted to do.
"The immediate thing is to try and replace him, which isn't easy.
"We're hoping eventually that Stewart Downing and young (Fabian) Delph will work towards replacing him."