Tony Pulis will check on the fitness of Patrick Bamford and Stewart Downing ahead of Saturday's match against Bristol City (3pm), while Mo Besic remains a doubt.
The Boro manager revealed in his weekly press conference that Bamford and Besic, who both made way at half-time against Sheffield United on Tuesday, are concerns, while the medical team will also be keeping an eye on Downing.
"We've got one or two with knocks that we're hoping will train today, and we'll see how they train and go from there," he said.
"Patrick's got a little hamstring issue, Stewart's had a little knock as well, so we'll see where they are."
Grant Leadbitter will also miss Saturday's match as he serves a suspension after being shown a red card at Bramall Lane on Tuesday.
"He's be brilliant, Grant," Pulis said.
"He's a great lad around the football club. As a captain, and as an individual I've been very impressed with him.
"Having said that, [Adam] Clayton was exceptional when he came on and if we get him playing as well as that for 90 minutes Grant will find it difficult to get back into the team."