TONY Mowbray is both frustrated and disappointed after Sunderland were hit with yet another season-ending injury - and the head coach has hinted at a further training ground blow.

Aji Alese has joined the likes of Ross Stewart, Corry Evans and Elliot Embleton on the treatment table with the defender ruled out for the rest of the season with a thigh injury.

And Mowbray has also revealed that another player, who he didn't name but described as an "important" member of his squad, hobbled out of training on Friday with what appeared to be a muscle injury.

Frustrated Mowbray has had to deal with one injury blow after another in the second half of the season, with his young Sunderland squad stretched to the limit.

"It's disappointing for Aji," he said.

"You have to get on with it, injuries are part and parcel of the game, but it does feel as if we've been hit pretty hard.

"When I look back when we were on the cusp of getting Ross fit, I was thinking we're going to have a brilliant second half of the season and we'd only get stronger. That hasn't been the case obviously.

"There's frustration attached. We've had to go to the well with the same players."

It's a disappointing end to what has been a hugely impressive first season on Wearside for Alese.

Mowbray said: "It was a great pick from the recruitment department. He brings versatility of being able to play centre-half and full-back. He's show he can join in and get higher up the pitch and be a threat to the opposition.

"It's going to be a blow but we have to deal with it and keep doing. I'm disappointed for him."

With Dennis Cirkin still unavailable, Mowbray must now decide who he brings into his defence at Norwich on Sunday, but he could yet have to go without another senior player.

He said: "Without giving away, there's an incident in training today where a player came off, a pretty important player, basically a muscle injury.

"It is frustrating. It's frustrating because we want to be competitive. I know we've fallen away but if you can put back to back wins together you're right back in the mix."

Asked whether Friday's training injury could be a long-term blow, Mowbray said: "I don't think so, I think it's a muscle injury. I haven't spoken to the physio department yet.

"It's never good when a player walks off mid-training."