The Blades’ skipper and top scorer limped off against Barnsley just before the international break after damaging a hamstring, and missed Saturday’s defeat at Stoke City as a result.
With only seven games remaining for the Blades to hopefully seal their place in the Championship play-off places, Blades fans are understandably keen to see their top scorer and talisman return as quickly as possible.
But that won’t be against Rangers, who are also chasing a top-six spot.
“Bill will be out,” Heckingbottom admitted.
“He wasn’t ready the other day, so we’ll be led by the medics and how Bill responds to his training with pushing on.
“It’s different with muscle injuries, and if you put them out there it can get worse. But Oli has trained today.
“It could drag on, but it’s the last little bit. When he did his work on Thursday and Friday, he felt the muscle when he was running really quick.
“It’s the last hurdle, making sure he’s fit enough to sprint. You’ve got to be explosive. You’ve got to be fit enough to help the team and have the confidence that it won’t get worse.”
Asked if United’s coaching staff may soon decide that it is worth gambling with Sharp’s fitness to try and get into the play-offs, Heckingbottom admitted: “We could do. But the decision is down to, is he fit enough to affect the team?”