The France star is thought to have grown frustrated at the lack of first-team options at the Old Trafford outfit over the past 12 months.
Manchester United manager Jose Mourinho has used the France international sparingly in the 2017-18 Premier League campaign.
The 22-year-old has been linked with a potential switch to their Premier League rivals Tottenham Hotspur and Chelsea FC over the past few weeks.
European giants Paris Saint-Germain and Inter Milan have been touted as potential suitors for the France international this summer.
Bundesliga giants Bayern Munich and Borussia Dortmund are also keeping tabs on the French star.
Mourinho is thought to be keen to sign Chelsea FC winger Willian and Real Madrid forward Gareth Bale in the summer transfer window.
The former Liverpool FC defender Nicol believes Martial has been given too much too soon at Old Trafford.
“He’s had too much too early,” Nicol told ESPN FC.
“For a guy with so much talent, he’s a bit part player.”
Manchester United ended up in second spot in the Premier League table last term to secure their place in the Champions League.
The Red Devils have signed Shakhtar Donetsk midfielder Fred and FC Porto defender Diogo Dalot in the summer transfer window.
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