Injuries to Gary MacKenzie and Andrew Davies and a one-match ban for Christopher Routis have left City chief Phil Parkinson with some selection issues in central defence ahead of Saturday's match at Gillingham.
After playing in the position several times for Notts County last campaign, Liddle partnered Rory McArdle at the back following Routis' red card against Preston North End on Easter Monday.
Along with Liddle, Tony McMahon is also an option at centre half for Parkinson having featured there for Blackpool in the Championship on more than one occasion this season.
Liddle said: "It is a position I have played quite a few times down my career, in particular at Notts County.
"If called upon, I'm able to deputise if needed.
"As many injuries as we do have at the back though, there are still options for the manager.
"He's brought Macca (Tony McMahon) in, who is obviously chomping at the bit for a start.
"He came on recently at Doncaster and did really well.
"The manager does have options and I'm sure whoever he picks will do a decent job."