NEW signing Adam Thompson is facing a month on the sidelines after suffering an injury in Rotherham United training.
The centre-half, who has yet to make his debut following his last-August move from Bury, pulled up at the club's Roundwood complex last week.
"Thommo is out for four weeks," said manager Paul Warne whose side are in League One action at Sunderland tomorrow night.
"His ligament has come away from his bone in his leg. It doesn't need surgery, which is good news."
Thompson, aged 26, had been named on Rotherham's bench in recent weeks before missing out as Warne's men hammered Bolton Wanderers 6-1 at AESSEAL New York Stadium last Saturday.
"The injury is a blow," the boss said. "Thommo has been good in training. With all the games coming up, there's no doubt I'm going to use everyone."
He joins fellow new boys left-back Trevor Clarke and winger Chiedozie Ogbene in the treatment room.
Midfielder Jamie Lindsay was substituted because of a knock in the win over Bolton but the Millers are hopeful he will be available to face the Black Cats.
Two-goal striker Carlton Morris and winger Jake Hastie, who also scored, were also taken off but only to keep them fresh for the trip to the Stadium of Light.
"Jamie got a bang on his ankle," Warne said. "We were just saving legs for Tuesday night really with the other two.
"Without wanting to sound 'big time', I felt we were in control of the game. All my subs can play. It wasn't like I was weakening the team."
Rotherham will be without Kyle Vassell against Sunderland but the striker, who has been out with a hamstring problem, is on course to return to the squad for this weekend's home clash against Shrewsbury Town.
Along with Morris, record signing Freddie Ladapo was also on target twice against Wanderers as the £400,000 man opened his New York account.
"Strikers obviously want to score goals but it's about more than that when you play up front for me," Warne said. "You have to do more."
Right-back Billy Jones made the bench last Saturday after recovering from a foot complaint.