The Senegal international midfielder, who is on a seasons long loan deal from Liverpool, has made just one appearance since arriving from Anfield during the January transfer window.
Diao picked up a calf strain in the game against Fulham at St Andrew's on 22nd January and has missed the last four fixtures, although he would not have been allowed to play in last weekends game against Liverpool anyway.
However, Diao has now stepped up his training and is targetting the game at Sehurst Park on 26th February for a possible return to manager Steve Bruce's first team squad.