The former Everton man injured his hamstring in City's 1-0 win over Aston Villa in the first half and now could be out for as long as four weeks.
Silva told Sky Sports News: "It's a great shame he is injured again after getting back into the team and playing in the last two games.
"I have never been injured in the same way, but I know what it's like to have an injury where you can't see the end of the tunnel. He has worked really, really hard already, but he needs to keep concentrating and he will be back with us."
City face Barnsley in the FA Cup this weekend as they look to reach the last four of the competition.