Everything Sunderland sporting director Kristjaan Speakman said about free agent market and striker cover before Ross Stewart injury blow

Stewart picked up a thigh issue during the warm-up ahead of Monday’s 1-0 defeat at Middlesbrough.

Tony Mowbray confirmed: "Ross will be out for six to eight weeks - it could be a little longer, but that will depend on his rehabilitation and the way his body reacts.

"He's a really positive guy and we hope that he will be a quick healer, so we will take it game by game and hopefully he returns quickly.”

The lack of striker cover was already causing fans concern before the injury to Stewart.

Last week, Sunderland's Sporting Director Kristjaan Speakman was questioned about transfer business and said that the club are unlikely to add a free agent to their squad after deadline day passed without any further additions.

Speakman said on Thursday that he would assess those still without a club, but that he didn't feel it was a necessity.

"We're not looking at the free agents market like we need to find a player," he told The Echo last week after the transfer window closed.

"Naturally, as I said last year, we'll look at it and what the availability is.

"We don't need any players if that's the question, but at the same time we're always vigilant and if we can improve then we'll look to do that."

Sunderland's lack of deadline day business has left some concerns with supporters over a couple of positions where further recruitment had been expected.

No replacement was found for Nathan Broadhead, who was close to joining on a permanent basis before opting to move to Wigan Athletic on loan.

And there was no extra defensive cover found despite Dan Ballard's foot injury.

Luke O'Nien's versatility is therefore going to be key moving forward.

Speaking last week, both Speakman and Tony Mowbray feel they have the cover needed further forward.

"We think we've got a lot of flexibility in the group, which is something that Tony alluded to earlier," Speakman said.

"You've got Ross and Ellis who are your out-and-out nines, then you've got Amad and Leon [Dajaku] who can play up there and some younger ones beneath if we feel the time is right and if they can get Tony's trust.

"We think we've got that flexibility, externally there'll always be that discussion about the right balance and as soon as you get an injury the expectation is you'll buy another player, and that's just not reality.

'We feel we've got tactical flexibility and we can get through to the next pit-stop if you like in January, hopefully Dan will be back after the World Cup break.

"We have to see those players play, lads like Aji Alese need to play and grab that opportunity. You can't just keep filling the spot in front of him,” he added.

Sunderland host Millwall at the Stadium of Light on Saturday.

Meanwhile, Dennis Cirkin was also forced off during the match against Boro with a hamstring problem, yet the defender should be available after the upcoming international break.