The 25-year-old Scotland international came close to joining Birmingham earlier in the summer and is keen to leave Pride Park.
Ben Watson of Crystal Palace continues to be linked with the Reds however and his desire to exit Selhurst Park may be matched by Eagles boss Neil Warnock.
After freezing Watson out of the early-season action, Warnock named him in the side for Tuesday's League Cup tie at Leeds, only to be rewarded with a 4-0 hammering.