The 25-year old striker has started just four times in the Premier League for a total of 16 appearances for United this season, which has prompted plenty of frustration according to the El Tri boss.
"He seemed well but he is a bit frustrated because he doesn't play despite training well and the truth is that when he does play, he makes a huge effort on the pitch," Herrera told Raza Deportiva.
"He is a bit frustrated because the current manager doesn't give him many chances, but he is committed and doing what he can to become a starter.
"He likes to work and likes to show determination to achieve his goal."
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