Jose Mourinho will not turn to Bastian Schweinsteiger even if Paul Pogba is ruled out of Manchester United's trip to Swansea City through injury.
Pogba limped off after 30 minutes of Thursday's 2-1 Europa League loss at Fenerbahce after appearing to take a knock to the thigh in a challenge with Souza.
Schweinsteiger returned to first-team training with United this week having been exiled by Mourinho.
The Portuguese said ahead of the Fenerbahce match that former Germany captain was primarily with his group to make up the numbers for training drills and build fitness if he elects to make a January move.
Despite saying he did not know whether Pogba would be able to feature at the Liberty Stadium on Sunday, Mourinho was adamant he did not view Schweinsteiger as an alternative.
"No, no," he told reporters when asked whether the 32-year-old was in contention.
"Because I decide and I decide no. It is too early for him.
"He is training with the team for three or four days. He is not ready to play football at that level."
United fell behind in Istanbul after Moussa Sow's spectacular overhead kick with barely a minute on the clock.
They suffered a similar fate when Pedro scored inside 30 seconds to prompt a 4-0 loss at Chelsea and Mourinho wants to see more evidence of strong attitude and leadership in his squad.
"It can happen everywhere. There are so many examples in football that people score goals in the first minutes and nobody is free of that," he said.
"But, a stronger attitude, leadership on the pitch, defenders in control of the emotion and in control of the organisation - it is easier to be strong and easier to be solid."
Injuries to Chris Smalling and Eric Bailly have resulted in left-sided duo Daley Blind and Marcos Rojo being paired at centre-back and, while he praised the application of both players, Mourinho believes the partnership is not helping his team's stability.
"You never saw a Jose Mourinho team play with two left backs as central defenders. I cannot be critical of the boys because they do what they can. The try their best," he added.
"For Daley it is even more difficult to play as a central defender on the right side. It is completely uncomfortable for him. He cannot be a good builder of the game when this is one of his good qualities.
"Marcos is trying hard and is fine but it is a very important starting point for the stability of the team. It is hard to have a strong team."