Nottingham Forest have submitted an application to the Premier League to re-register Steve Cook, reports the Telegraph.
Forest deregistered the 31-year-old centre-back last month to make way for their new signings.
Cook turned down a loan move and was left out of Forest’s 25-man squad for the second half of the season.
Championship clubs Blackburn Rovers, Luton Town, Stoke City, Reading and Cardiff City were all interested in him.
The Tricky Trees are down to their bare bones in central defence and are without three centre-backs.
Scans have revealed Scott McKenna and Willy Boly are set for extended periods on the sidelines. Summer signing Moussa Niakhate is also yet to be fully fit after a long-term injury.
McKenna is out for up to six weeks while Boly could miss three months of action after they sustained hamstring injuries last Saturday.
Cooper is left with only Felipe and Joe Worrall as his options ahead of Saturday’s game with Manchester City.
Forest will disclose medical reports on Boly’s condition in their application to boost their case.
They reckon their appeal will be successful as Cook is already registered. The City Ground club also hope their injury crisis will convince the Premier League.
The club are also without Dean Henderson, Ryan Yates, Cheikhou Kouyate, Omar Richards and Giulian Biancone.
The outcome of their application is expected before noon tomorrow.
Forest are 14th in the Premier League after 22 games, with six points separating them from the relegation zone.
Man City are top of the table and will be looking to consolidate their position with a victory this weekend.