Jose Mourinho says Ander Herrera coming off injured in Manchester United's 0-0 draw against Sevilla is "proof" he was not 100 per cent fit, despite assurances from the club’s medical team.
Herrera has struggled with a muscle problem in recent weeks but was passed fit to play at the Ramon Sanchez Pizjuan.
However, the Spain international was forced off after just 17 minutes of the Champions League last-16 tie with what appeared to be a hamstring injury.
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"I think it is a bad injury," said Mourinho. "He had a small injury that stopped him for the last couple of matches but the medical team said he was 100 per cent ready for the last Saturday.
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"It didn't look like he was fully fit. We didn't play him to give more work and more protection, but it looks like he was not fully fit.
"The medical department gave him fully fit. They gave him fully fit Saturday and he trained Saturday, Sunday, Monday, Tuesday, and he looked fit.
"The way he was playing during the time he was on the pitch, I think he showed that intensity that is only possible when you are fit.
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"He was pressing really high, we start the match not giving one inch to (Ever) Banega, pressing him really high. Ander was one of them, Scott (McTominay) was the other one, and you only do that when you feel really good.
"Then the back-heel creates a contraction in the muscular area where he had a fitness problem, and now we have the proof that he was not 100 per cent fit."
Herrera was playing his first game for United since the 2-0 defeat to Tottenham at Wembley on January 31.