The France international enjoyed an impressive debut season for United after signing from Monaco in 2015.
But this campaign has been much more of a struggle with just six goals in 20 games and he was not included in the squad which draw 1-1 with Stoke on Saturday.
Manchester United's predicted team to face Hull in EFL Cup
Tue, January 24, 2017
Express Sport brings you Manchester United's predicted XI to face Hull in the EFL Cup semi-final second leg
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Who will Jose Mourinho start against Hull in the EFL Cup semi-final second leg?
Responding to a quote from Mourinho where the United manager said Martial was failing to take the opportunities given to him, Neville tweeted: “He's only achieving a very small part of his potential. He ranges from sensational to disinterested.
“Let's hope he gets going now!"
Anthony Martial has had a disappointing season
Ahead of tonight’s EFL Cup semi-final second leg with Hull, Mourinho made clear his thoughts on Martial’s situation.
“I don’t think he lost his focus,” he said.
He's only achieving a very small part of his potential. He ranges from sensational to disinterested . Let's hope he gets going now! https://t.co/fORTYlAx2Z
— Gary Neville (@GNev2) January 26, 2017
“I just think he didn’t catch with both hands a big opportunity he had. When we spoke about Memphis Depay [leaving United] we spoke about it being the only position where we have an over-booking of players.
“We have still five players for this position. I cannot give one player chances to play and kill the others.
Jose Mourinho wants an improvement from Anthony Martial
“To kill the others, I think I already did that with Memphis by considering him the last option and by not giving him any option. But with the other guys I think you would be asking me why Mata is not playing or why Marcus Rashford doesn’t have a chance, or why Jesse Lingard, a national team player, is not playing.
“We have Rashford, Lingard, Mata, Mkhitaryan and Martial, and I cannot give the same player chance after chance after chance and not consider the effort of the others.
“Anthony played against Liverpool, a big match for us and a big match for him, too. Then the next game I went to Mata and Mkhitaryan. This is the situation.”