Manchester United have been told they made a serious mistake not cashing in on Bruno Fernandes over the summer when his stock was at an all-time high, while a second Red Devils star has also been told he is in “dangerous territory” with regard to his future at Old Trafford.

The 33-year-old Fernandes is undisputedly regarded as the best signing United have made in the post-Sir Alex Ferguson era, playing a part in an incredible 222 goals and assists (112 scored, 110 assists) in 340 appearances since a £57m move from Sporting CP nearly six years ago.

But there have been serious signs that Fernandes’ impact on games is declining this season, with the player suffering an alarming drop-off in form, while a public criticism of the club’s tactics in a recent Champions League loss to Como also saw him dropped to the bench.

While that spat has been put to bed, there remain some very serious questions over Fernandes’ future at Old Trafford.

With his contract due to expire at the end of the season, the two parties remain at loggerheads over a would-be extension, with sources revealing the club are unwilling to meet his colossal salary demands.

And in light of that, our transfer correspondent Graeme Bailey exclusively revealed this week that the player is now instructing his agent to look very seriously into future transfer options, with the possibility of a move away now becoming a much more tangible scenario.

To that end, sources have revealed exactly where the player could end up, with a January exit not entirely impossible.

Now pundit Dean Saunders has told United they blundered badly by not cashing in on the player over the summer when the reigning Player of the Year’s stock was at an all-time high.

“I said in the summer that Manchester United should have sold Bruno Fernandes for £100m, and everyone booed me off!” Saunders told Footy Accumulators. “To be fair, when you look at his goal record, he’s scored a lot, but that’s because he’s playing number 10 for Man Utd – you have the freedom to go where you want, and you don’t have to track back.

“I think Bruno’s behaviour changed a bit against Chelsea on Saturday – he seemed to be encouraging players a bit more, but his actual sprinting and getting around the pitch didn’t. He’s obviously talented, but I just don’t see it with him.”

Lisandro Martinez told he needs to learn his place

Fernandes was not the only United player that Saunders turned his vitriol towards, with anger also displayed at the recent behaviour of Lisandro Martinez.

The Argentine defender, who it was reported earlier this season was fighting for his future at Old Trafford, publicly criticised the club’s summer transfer business following a Champions League loss to Atletico Madrid, before conceding a penalty and then seeing red in last weekend’s 2-0 loss at Chelsea.

It has since been claimed that United are willing to sell the Argentine in January, with the player having already agreed personal terms with his next club: a LaLiga giant.

Either way, Saunders thinks United are right to try and get rid of him, branding the player a ‘walking red card’ and telling him he ‘needs to learn his place’.

“Isn’t it unbelievable how Christian Romero and Lisandro Martinez won the World Cup with Argentina, without getting sent off? They both look like walking red cards,” Saunders added.

“They need to know their places. How can Lisandro come out and criticise Michael Carrick, who pays his wages?

“He’s been at fault for about six goals this season, and he’s having a go at the people above him. He’s in dangerous territory at the club.”

Sources revealed earlier this week that United are closely following an impressive Como star as a possible heir to the defender in the heart of defence.

We understand the Red Devils are also weighing up an approach to Fulham for one of their more impressive stars, who would prove a like-for-like replacement.