Tony Mowbray reveals the positions in which Sunderland were still trying to recruit on deadline day

Sunderland ultimately decided that while not direct replacements for either Stewart or Ellis Simms, Amad Diallo and Leon Dajaku could offer cover through to the next transfer window.

Former head coach Alex Neil had been clear that he wanted a third striker in the ranks after a move for Nathan Broadhead fell through.

Simms will have to lead the line for the next six to eight weeks as Stewart recovers, while a much shorter-term injury to Dennis Cirkin has left some obvious gaps in defensive areas.

Sunderland were known to be pursuing a loan deal for Brighton defender Jan Paul van Hecke in the closing stages of the window, before then head coach Graham Potter decided he would stay and be a part of his plans moving forward.

Mowbray has also explained that specialist cover for Corry Evans was a position where Sunderland were close to doing business.

"Not really, no," Mowbray said when asked if Sunderland had been asked to signing a striker on deadline day.

"One was a pretty flexible defensive midfield player, someone who could play in midfield and cover Corry Evans' position and also go out wide and play in the full back area.

"One was a defensive player but there was never in my mind a stick-on centre-forward, I think that's why Ellis Simms was brought in. He's done so well that he needed to be in the team.

"It's going to come down to how we play moving forward, there's no reason you can't play with one centre-forward and lots of clever players behind him to try and service him and also try to get into the box themselves.

"I'm a pretty flexible manager, I look at the players we've got and try to pick a system and a way of playing that helps them."

Sunderland were also exploring the possibility of bringing experienced goalkeeper Vito Mannone back to the club in the final days of the window, but he instead opted to join Ligue 1 side FC Lorient.