Former England captain Alan Shearer has called on Marcus Rashford to knuckle down and get his Manchester United career back on track as he insisted it will be difficult for the forward to seal a move away from Old Trafford in January.

Rashford, 27, was left out of four consecutive squads by manager Ruben Amorim in December - including games against Manchester City and Tottenham Hotspur - and later admitted it would be the right time to leave his boyhood club.

On Thursday, the Manchester Evening News reported that Rashford had rejected three offers from Saudi Pro League clubs - worth up to £35m - as his future at United remains uncertain. Meanwhile, on Friday, Rashford was linked with a move to Napoli as part of a swap deal that would see Victor Osimhen move in the other direction.

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Shearer, however, has called on Rashford, who has made over 420 appearances for United since his debut in 2016, to apply the "correct attitude" and force himself back into Ruben Amorim's plans. Speaking to Betfair, the Premier League's all-time leading scorer said: "For Marcus Rashford, hard work and the correct attitude will see him get back to his best.

"I don’t know what’s gone on, but something must have happened for him to do that interview and say that it’s best for him to leave Old Trafford. You can’t just flick a switch and get back to your best form, we all have difficult periods where you might not be playing or can’t find the back of the net.

"There’s only one way to get through that; and that’s to get your head down, work hard and then things should change for the better. I think that it’s too early to talk about his England career - he needs to sort himself out and the club needs to sort themselves out as well.

"I don’t think that he can afford yet to be looking at an England career, which has gone pretty stale. He hasn’t been picked for such a long time now, and he hasn’t been playing recently, so I don’t think that anyone can entertain any England talk yet with him."

On a potential January exit, Shearer added: "There have been reports about a swap deal with Napoli for Rashford with Victor Osimhen going to Old Trafford. We’ve seen other players go to Serie A and get their career going.

"However, I think that where Marcus is concerned, he’d have to look at every option - to see whether one fits or suits him, as well as Manchester United, which is perhaps the bigger consideration. Whether that can be done in the next month or so, or whether he’s going to try and force his way back into the Man United starting eleven, I don’t know.

"I do get the idea that it would be very difficult to get a deal done, because of all the different angles and parties involved with the deal. I do think that it will be difficult to get a deal done this January, regardless of a loan or permanent deal. It's a really difficult transfer to do.

"There’s a lot to do and so many aspects to a transfer. First of all it’s about agreeing a fee, secondly agreeing a salary - he’s on a huge wage right now at Man United and I’d be amazed if somebody in the Premier League would be willing to match that.

"But just because nobody reports it, doesn’t mean that there’s no interest from Premier League clubs in signing him. Nothing really surprises me in football, and just because there’s been no talk doesn’t mean that there hasn’t been any enquiries whatsoever.

"So far, yes. Last six months, there is no progress there, we are far away from any progress, so we just need to wait and see."