Sunderland boss Chris Coleman described his side as "naive and nervous" following their 2-0 FA Cup defeat to Middlesbrough on Saturday.
The Black Cats were booted out of the competition at the first time of asking by Middlesbrough, who secured the victory through goals from Rudy Gestede and Martin Braithwaite.
Coleman, who questioned the loyalty of his players following the defeat, said that "one or two players" could be contributing more to the side.
"One or two of [the players] are out for a few months and have had scans, but could one or two be doing a bit more to be with us? Yes," the Welshman told The Mail.
"We're in a dogfight and you don't go into a dogfight with kittens, that's for sure. I just need whoever is ready for it and the boys today were ready.
"We were naive and nervous but at least they were out there having a go. These are the players we need, and they need support in terms of strength and depth."
Sunderland, who sit bottom of the Championship table, lost top scorer Lewis Grabban to Bournemouth on Friday after the Cherries recalled the striker from his loan deal at the Stadium of Light.
