Allardyce had tried to sign Liverpool defender Djimi Traore on loan but the Anfield club where only willing to do business over a permanent deal so the Bolton boss has now turned his attentions to the former England player Gray.
Gray, who recently returned from a loan spell with Scottish champions Celtic, has made over 400 appearances for his hometown club but Black Cats manager Mick McCarthy is keen to get the left back off the clubs wage bill and the 29-year old is someone Allardyce is keen on signing providing Celtic release the players registration.
"Michael Gray could be a possibility now he has returned from Celtic. Sunderland would probably want to move him on so we might be able to do something, I'll be making an enquiry" he confirmed.