The forward had his contract cancelled by the Sky Blues early after a first promising year with City's Academy and Reserves and returned to his native Ireland to play for Cork City. O'Donovan did well there and was plucked out by Sunderland boss Roy Keane to join The Mackams in 2006. He was loaned out after making 17 appearances and will join City on a three year deal which starts on July 1st after his contract expires.
"Being back here is all a bit surreal to be honest. It's a bit strange to be back but I'm delighted to be here because it's a great opportunity for me," O'Donovan said to Sky Blue Player.
"I just want to get going now. I know a couple of faces around the club which will help me settle a bit quicker but to me it's like a move to a new club.
"It's a fantastic new stadium, a new manager and I don't want to give the fans any less than 100 per cent. I won't settle for less than that I'm sure they won't either.