Manchester United defender Lisandro Martinez is back on the grass in a huge injury boost for Ruben Amorim.

The Argentinian centre-half has been sidelined since February, after suffering a ruptured ACL in a Premier League match at Old Trafford against Crystal Palace.

He underwent successful surgery later that month, thereby marking the beginning of a long road to recovery.

With the left-footer still not participating in first-team training, Saturday’s game against Chelsea will likely come too soon for him, though a return after the upcoming international break could be feasible.

News of Martinez’s nearing full recovery emerges at a time when pressure is intensifying on United boss Ruben Amorim due to a poor start in his second season.

Lisandro Martinez revealed that he’s back on the grass in an Instagram post on Wednesday

The Argentinian has been out of action since suffering a ruptured ACL back in February

Following a promising performance against Arsenal on the season’s opening day, they drew at Fulham before facing a disastrous defeat at League Two’s Grimsby Town. This was followed by a last-minute victory at Burnley, their first of the season, and Sunday’s 3-0 loss at Manchester City.

Sitting fourteenth in the table, Amorim’s side are yet to keep a clean sheet and have scored just one goal from open play in the Premier League. 

The United boss however insisted he will not change his 3-4-3 system in the coming weeks post-match at the Etihad. 

Amorim said: ‘‘I am not going to change. When I want to change my philosophy, I will change. If not, you have to change the man.

‘Losing faith in your ability to turn the situation around? No, that is not the way. I believe in my way and I am going to play my way until I want to change.

‘My message (to the fans) is that I am going to give everything, always thinking about what is best for the club. The rest is not my decision. Until I am here, I will do my best. I really want to win games.’

It’s thought the Portuguese coach retains the backing of the Manchester United board and Sir Jim Ratcliffe for now, but if results don’t improve that may well change.  

It’s understood some players have never been comfortable with the 3-4-3 system that was introduced when Amorim succeeded Erik ten Hag in mid-season last November.

His return comes at a time where pressure is mounting on Red Devils boss Ruben Amorim

After United’s 3-0 loss at Man City on the weekend, Amorim insisted he won’t change his ways

His side – and goalkeeper Altay Bayindir – are yet to keep a clean sheet this season

United hoped that giving the 40-year-old a full pre-season to work with the squad, and £236million for new signings to fit his system, would see an upturn in results after the club’s worst campaign in more than half a century. 

The players are still struggling to get to grips with Amorim’s style almost 11 months after he took over, and even one of his staunchest allies, captain Bruno Fernandes, is believed to be unhappy operating in a deeper midfield role.

United sources say it would be wrong to suggest that Amorim has lost the dressing-room, and insist he still has support among the squad.

But former United star Wayne Rooney has questioned whether the players understand the system, and claimed that United are going backwards under Amorim who has won just eight of his 31 Premier League games.

‘We just watched it a lot of the lads who played the game today, and I don’t think anyone can understand and comprehend what is going on,’ said Rooney, who was in South Korea for a legends’ game with some of his old United teammates.

‘We are all watching it, and we all struggled to give what we see how Man United play. What are the patterns? What are we seeing what might improve the team moving forward? We have all played the game at the highest level and it is very difficult to see that.

‘Speaking to Rio (Ferdinand), we want to support the team and the manager the best we can, but we also have to be honest as the fans are not fools.

‘Rio was out with the team in Chicago pre-season. I go to the training ground a lot with my children, and it does put us in an uncomfortable position. But we have to be honest with what we’re seeing. Frankly, it is not good enough.’