Former Manchester United defender Rio Ferdinand has said there is "no way back" for Marcus Rashford at Old Trafford after his commitment to the team was questioned by manager Ruben Amorim.

The 27-year-old has not played for United since Dec. 12, with Amorim saying he would rather play his 63-year-old goalkeeper coach Jorge Vital unless the forward starts to "give the maximum every day in training and in life."

ESPN reported last week that Rashford's representatives held face-to-face talks with Barcelona about a potential move before the transfer deadline, and Ferdinand said the forward will have to leave Old Trafford following Amorim's statement.

"If I was the player the manager said that about, my heart, my pride, my ego -- it's embarrassment," Ferdinand said on his YouTube channel.

"For someone to question your application, to question you giving 100 per cent for the team, saying you're lacking effort and taking shortcuts, that's a damning comment. There's no way back for Marcus after that.

"If he did come back that means other players can take their foot off the gas and have a way back into the team and take shortcuts."

Rashford has made more than 400 appearances for United since joining the club at aged seven and won the Europa League, two FA Cups and two EFL Cups.

His start under Amorim was positive, he scored in the managers first game in charge and a week later scored twice in United's 4-0 win to Everton.

However, he said last month that he was ready to seek a "new challenge" away from Old Trafford after being dropped for United's 2-1 win against Manchester City.

Ferdinand added that he felt Rashford would have made a public statement if Amorim's comments about his commitments were false.

"For me, if it isn't true, I'm coming out all guns blazing. I'm holding a press conference and saying 'I'm not having anyone say that about me'," Ferdinand said.

"I would love to sit across the table from Marcus and look into his eyes and see if he could say that. If you can't, you have to look at yourself."