Caretaker boss Gary McSheffrey was tightlipped on the nature of Anderson’s injury but admitted the Rovers captain may not feature against the Black Cats.
“We’ll give Tom as much time as he needs,” McSheffrey said. “He got a little knock and that’s all I can say at the minute.
“I don’t know the full details of it yet. He’s carrying a little something and we’re hoping it’s not too severe.”
Close had been tipped to make a return to action over the festive period after making good progress with hamstring and knee injuries but is not clear of the issues.
McSheffrey said: “Ben has not made the progress we were hoping for.
“He did feel some discomfort when he was cracking on with probably a week’s worth of training and looking like he was close.
“It’s set him back probably a week or two.
“The one thing you don’t want to do with Ben Close is rush him too much and lose him for the season.
“We’re trying to get him back in a timely manner but as fit as he can possibly be for his own health and safeguarding.”
McSheffrey revealed Rovers’ injury situation has not particularly improved since the win over Shrewsbury Town a fortnight ago.
An outbreak of Covid-19 within the squad saw last weekend’s scheduled trip to Lincoln City called off and has hampered training over the last week.
While injured players are not set to return, Rovers are likely to have available the vast majority of those forced into isolation due to coronavirus.
McSheffrey said: “We’ve had a couple back in training today [Thursday]. With the new guidelines they’re able to come back in.
“The remaining boys will be back in for Boxing Day.
“We’ve had no real new ones in recent days so we should have the bulk of the players back for Boxing Day.
“Ultimately you want your strongest squad to select from for every game but you can only control what you can control and it’s out of our hands.
“If someone is missing, it’ll give someone else an opportunity. We’ll find solutions rather than looking to make excuses.
“If we need to play a couple of youngsters, we need to play them and it’s an opportunity for them.
“Dan Gardner has trained a bit and a couple are out doing running with the physio.
“In terms of the bulk of injuries that we had, there’s not many training with the group at the minute.
“There’s a couple doing fitness work but there’s not been massive improvement in that area.”