The Blades have recalled Paul Shaw from his loan spell at Rotherham United early due to injury's to Ashley Ward (knee) and Jack Lester (shoulder).
Shaw, who netted twice for the Millers whilst on loan is expected to start upfront alongside either Andy Gray or Jonathan Forte. New loan winger Tommy Black from Crystal Palace should make his full Blades debut.
The Welsh Dragons will be without former Blades keeper Andy Dibble as he is ruled out, also out is Dennis Lawrence (ankle), Hector Sam (knee) and Steve Roberts (ankle).
Former Tottenham Hotspur front man Chris Armstrong is out after he was sent-off at the weekend.
Stat of the Day: Blades first ever meeting against Wrexham was away in Second Division during 1978/79 season where United lost 4-0,surely lightening can not strike twice?