The Mexico manager says his striker is unhappy with the playing time he has received since David Moyes took over at Old Trafford.
"Chicharito is frustrated because the current coach doesn't give him many minutes, but he continues to be very committed," said Herrera, who was talking about his tour visiting Mexican players based in Europe.
The 25-year-old had been quiet on the subject of playing time, despite the diminishing opportunities he has received for Manchester United over the past two seasons, but published a cryptic statement on his Instagram account Sunday following his team's 2-2 home draw against Fulham.
"The time to speak about so many things will come," he wrote, in Spanish and English.
Chicharito's agent, Eduardo Hernandez, told ESPN Deportes in late January that clubs from Spain, Italy, France and Germany had shown interest in the former Chivas player and that he had met with officials at Manchester United to discuss the player's future, but was told the Mexican international is a part of the club's plans.
Hernandez has started just four Premier League games this season, netting two goals.