The 23-year-old is incredibly talented, but he has been unable to build on his early promise at Old Trafford after enduring three frustrating seasons.
With Romelu Lukaku joining Inter Milan, Martial now has a great opportunity to silence any critics and finally fulfil that potential.
When Anthony Martial made his dramatic debut against Liverpool in 2015, Man United fans thought they had unearthed another world-class talent.
The French forward had exploded onto the scene in England, and he then followed that up with two goals in his first start for the club.
His dribbling abilities, brilliant technique and clinical finishing made him an instant fans’ favourite at Old Trafford.
United’s new number nine also showed excellent versatility by playing up front and on the left-wing during his debut season.
While many players struggled with Louis van Gaal’s stifling tactics, Martial was still able to thrive. The then 19-year-old was United’s top scorer that season with 17 goals and he also registered nine assists.
"I have already said in many press conferences after matches that Anthony Martial with his age is an exception, because he has also played every match," said Van Gaal.
"To play every match then you have to be very strong and consistent because every week I shall compare every player with his competitor. It is fantastic what he is doing."
As United finished fifth in 2015/16, Martial’s emergence was one of the few bright spots in a difficult season for the club.
The forward was regarded as United's future and was potentially someone that the next manager could build his team around.
Problems with Mourinho
After a promising first season, things soon started to go wrong for Martial when Jose Mourinho was appointed as Van Gaal’s successor.
Mourinho immediately sought a more experienced striker to lead the line and signed Zlatan Ibrahimovic, who was given Martial’s number nine shirt.
Martial’s confidence was knocked and his form soon dropped as he found himself on the bench under the new manager.
The forward only made 25 appearances in the Premier League during 2016/17, scoring an underwhelming four goals.
Martial never earned Mourinho’s trust and the pair clearly didn’t see eye to eye as the manager often criticised his poor body language and application.
He also struggled with inconsistency under Mourinho, and Martial has been unable to match the standards that he set in his first season.
Ole Gunnar Solskjaer’s appointment as Manchester United manager looked to have sparked new life into Martial, and he was rewarded with a new long-term contract in January.
However, his form nosedived in the second half of the season and he only scored another three goals in 2019 as fans started to lose faith in the 23-year-old.
Four years after that debut, Martial is now in limbo as his career has stalled and he hasn’t developed as many people expected.
While the forward still has plenty of supporters, patience is now starting to wear thin as he is no longer a promising teenager.
During this pre-season, Ole Gunnar Solskjaer has mainly played Martial centrally in a 4-2-3-1 formation for United.
The striker has impressed Solskjaer by leading the line well, showing good movement and scoring twice over the summer.
"Anthony can be a world-class forward. The way he has come back to pre-season now, how he is in training, his attitude is absolutely spot-on. There are a couple of instances that you can see with Anthony, in the way he works for the team," Solskjaer said to ManUtd.com.
"He has got the quality and talent. He's going to score goals and his work-rate is improving. I expect him to be even better than last season."
Lukaku has joined Inter Milan and United haven’t signed a replacement, so Martial has been given the number nine shirt and looks set to be their first-choice striker this season.
The Frenchman has already shown that he is clinical in front of goal and he has excellent composure in the penalty area.
Last season Martial had the best shots-to-goals conversion rate in the Premier League, scoring 10 times from 39 shots.
However, there will now be added pressure on Martial to step up and become the consistent goal scorer that United need if they are going to get back into the top four.
He clearly has the talent to be a success at Old Trafford, but this season might be his last chance to prove that he should be United's main centre forward.
If Martial fails to deliver and has another underwhelming campaign in Manchester, the club may just decide to cut their losses and give up on him once and for all.