Bristol City boss Keith Millen is hopeful on-loan defender Steven Caulker will be fit for the game.
Caulker was initially very doubtful for the game after limping out of the FA Cup third-round defeat to Sheffield Wednesday last weekend.
He suffered a hip injury following a collision with team-mate David James and returned to parent club Tottenham for treatment.
"It didn't look too good to begin with. I didn't think he would be available for this Saturday, but now it looks as though he might be," said Millen.
"I spoke to someone at Tottenham on Tuesday and he told me the scan was just a precautionary measure. I'm certainly not ruling Steven out of the Middlesbrough game."
More good news for Millen is the return to fitness of captain Louis Carey. The defender has been out for two months with a series of problems, but came through a reserve-team game this week and is available for selection.
Another defender, Christian Ribeiro, is a doubt after sustaining a hamstring injury against Sheffield Wednesday. Liam Fontaine is on standby to come into the side, while forward Danny Haynes could also be recalled.
Boro boss Tony Mowbray is hoping to have several key men back at his disposal for the trip to Bristol.
Marvin Emnes (foot), Barry Robson (thigh) and Jason Steele (knee), who all missed the 2-1 FA Cup third round defeat at Burton, have returned to training this week.
The trio could all come back in, but midfielder Nicky Bailey is a major doubt after going down with a virus.
Mickael Tavares is out with a fractured toe which will sideline him for at least three weeks, while the club is awaiting the results of scans carried out on teenage striker Luke Williams after he damaged an ankle during the 4-2 FA Youth Cup victory over Doncaster in midweek.
Kevin Thomson continues his battle to return from the after-effects of his leg fracture, but Stephen McManus (ankle ligaments), Willo Flood (knee) and Rhys Williams (pelvis) are still out.