TONY MOWBRAY has admitted that Sunderland failed to recover from the blow of losing leading scorer Ross Stewart in the warm-up ahead of last night’s 1-0 derby defeat to Middlesbrough.

Stewart suffered a thigh injury moments before leaving the field ahead of kick-off at the Riverside, forcing Mowbray to replace him in the starting line-up with Patrick Roberts.

Roberts was unable to offer much of a goalscoring threat in the final third, and Mowbray admits his players struggled to alter their game plan in an attempt to accommodate the late change.

“The fact we lost Ross right at the end of the warm-up meant we had to readjust everything we’d worked on for two or three days in a two-minute chat,” said the Sunderland boss. “With total respect, if you’re playing Patrick Roberts as opposed to Ross Stewart, it’s a totally different game plan.

“You have to get it through the lines and into his feet, and get him turned, as opposed to Ross, who was going to be running in behind and threatening the space behind. You’re asking the lads to almost forget about all the stuff we’d done for two days and go and play a different game.

“That’s not meant to be an excuse – that’s just the reality of losing your talisman, who is scoring the goals and looking a real threat in every game.”

Stewart will be sent for a scan, with Mowbray fearing the Scotland international could be facing a lengthy absence.

“Ross did it shooting in the warm-up,” he said. “He’s popped a muscle in his thigh. It seems a very isolated spot, but whether it’s a tear in the upper thigh where he’s struck the ball, we’ll have to see. It needs a scan. It’ll either come back grade one, grade two or grade three, which will mean he’s out for two weeks, four weeks or eight weeks. Let’s wait and see.”

To compound Sunderland’s injury issues, Dennis Cirkin was also forced off in the second half of last night’s game after suffering a hamstring problem. Like Stewart, the defender will now have to have a scan to ascertain the full extent of the damage.

“It’s the same as Ross really,” said Mowbray. “I don’t know how bad it is. It’s his hamstring rather than his thigh, so that suggests a fatigue injury really with the repetition of games he’s played."