Petrov says it was heartbreaking seeing a star name, so in love with the game, not able to play.
He told Villa's website: "I'm really happy to see him fit again. He's raring to go. He worked really hard to get fit and I think he's going to add something very special to our team.
"We're looking forward to seeing him in action. I had a conversation with him straight after when he had the injury.
"This boy loves to play football and when you see someone who loves to play football unable to do it because of injury - and I was involved in that - then it's not very pleasant to see.
"But he's worked really hard getting back, he's put his mind to it and he's raring to go again."