The Germany international picked up a bug while on international duty last month and took longer than usual to recover.
When he started training again he had a fragile body
Schurrle, 24, has only started four Premier League games this season, but Mourinho says that he is now close to being fully fit once again.
“He was very ill,” said Mourinho. “He was back here and he took a good two weeks, because it was a bad one.
“I think that affected him a lot from a physical point of view. When he started training again he had a fragile body and, as a consequence, a fragile brain.
“But now he’s coming step by step. He was on the bench against West Brom, and played 15 minutes in the last match.”
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