TONY MOWBRAY is confident Ellis Simms can shoulder the goalscoring burden created by the absence of Ross Stewart – as long as he adopts a more selfish approach to leading the line.

Stewart will be sidelined for up to two months after tearing a thigh muscle during the warm-up ahead of Monday’s Tees-Wear derby defeat to Middlesbrough.

In his absence, Simms finds himself as the only natural centre-forward on Sunderland’s books, and while Mowbray will be tweaking his tactics to deal with Stewart’s unavailability, he will be heavily reliant on the Everton loanee.

Simms might just be 21, but he has scored three goals in his first seven appearances in a Sunderland shirt and his manager is confident he can continue to find the net without his strike partner alongside him.

However, he will be instructing the youngster to modify his game slightly in order to ensure his side are not left without a focal point leading their attack.

“I think Ellis will rise to the challenge,” said Mowbray, whose Sunderland side will be inactive this weekend, along with the rest of the clubs in the English footballing pyramid, as a mark of respect following the death of the Queen. “As long as he does not put too much of a burden on himself . That’s why the rest have to step up as well.

“I think for Ellis, the biggest challenge is to play between the sticks when the chances are created. I would never tell him not to work hard, but sometimes strikers who work too hard taking themselves away from the goal and chasing down channels , they are the ones crossing the damn thing when they should be in the middle putting it in the net.

“That is my message to him really. Be a bit more selfish, between the sticks. You have to work hard, and I am sure he will because it is in his nature, but be selfish enough to get in between the posts and finish the chances off.

“How did (Pep) Guardiola change (Raheem) Sterling from a five, six or seven goals per season player into a 25-30 goal-a-season striker? I don’t think he was teaching him anything about where he put his feet, it was about where he had to be. And basically, he now plays between the sticks and scores tap-ins every season.

“We have to get Ellis between the posts, whether he bundles the ball into the net or heads it . He just has to be there to finish it.”

Throughout this season, Sunderland have played with twin centre-forwards, with Simms and Stewart dovetailing effectively in attack.

Sticking with the same approach is no longer an option, with Mowbray accepting there is not a like-for-like replacement for Stewart on the Black Cats’ books.

The likes of Patrick Roberts, Alex Pritchard and Jack Clarke will be encouraged to make more excursions into the 18-yard box to ensure Simms does not find himself isolated, but there will have to be a shift in Sunderland’s style while Stewart is on the sidelines.

“I don’t see (Amad) Diallo being a replacement for Ross Stewart,” admitted Mowbray. “He is a totally different type of player. And I don’t see the young Costa Rican (Jewison Bennette) being a replacement because he is just a right, dynamic, fast dribbler of the ball. He hasn’t really got those physical qualities, so we probably have to find a slightly different way to play and create different type of chances but still make sure we get enough bodies into the box to score the goals when the chances are created.

“You have to be brave enough to break the lines and get in the box - this is what we’re talking to them about really. Let’s not have loads of the ball around their box, they have five men behind the ball, and we never actually play behind them or have a shot at goal.

“We have to go into the areas Ross Stewart goes into, and if it is not Roberts or Pritchard being able to sprint like him in behind, then the ones who can run fast - the likes of Clarke or a full-back overlapping - have to sprint in behind. The quality players have to play the ball in, and we have to get behind teams and hurt them.”