Roy Keane tears into Kobbie Mainoo's 'IDIOT' brother after wearing controversial T-shirt - and sends young Man United star a message over his lack of playing time

Roy Keane tore into Kobbie Mainoo 's 'idiot' brother Jordan Hames-Mainoo for sporting a 'Free Kobbie Mainoo' t-shirt for Manchester United 's chaotic 4-4 draw against Bournemouth - and warned the player that he may have squandered his chance to work his way in Ruben Amorim 's side.

Mainoo has played just one full 90 minutes under the Portuguese manager this season, featuring in the Red Devils' ignominious defeat to League Two strugglers Grimsby in the Carabao Cup .

The 20-year-old has subsequently played only from the bench and made just 12 appearances across all competitions since the start of the season.

As such, the player is believed to be looking to leave Old Trafford on loan come January in a bid to boost his playing time - something Keane suggested was a lesser move compared to fighting for his place in Amorim's squad.

'Are you telling me that he can't sit there for another six months? He might think the manager's on his way out in the summer,' Keane said on The Overlap's Stick to Football podcast . 'He's 20 years of age, what's wrong with sitting and learning your trade? And even if he's not getting a chance, we've all had to do it.

'Sometimes a manager is on your case and what you have to do is prove them wrong. Jamie (Carragher) made a point that he never felt like a regular at Liverpool , I never felt like that at United.

Kobbie Mainoo has been struggling for minutes at Man United since the start of the season

His brother, former Love Island star Jordan Hames-Mainoo, added fuel to the fire wearing a controversial t-shirt at Old Trafford on Monday

'Every day is your chance to prove yourself to the manager and when the manager is picking his team, (he thinks) 'he has to play'. He's got to get that in his mindset.'

Man United rejected Mainoo's intention to go on loan over the summer, with Napoli believed to be his preferred destination, but Amorim has since suggested that the player has not taken his opportunities to break into the first team - despite hinting that Mainoo's competition for his place is club captain and regular starter Bruno Fernandes.

'What's football about? The life of a footballer is about trying to prove people wrong,' Keane continued. 'There was chat about Bruno leaving the summer, he might leave next summer. Bide your time.

'I have no problem players going out on loan, it can work for everybody, but sometimes as a player, your biggest challenge is here at Man United and getting into that first-team.

'Even if the manager is saying "you're not going to get in over Bruno", prove them wrong!'

Keane also had sharp words for Mainoo-Hames, whose t-shirt stoked controversy on Monday evening, and did little to pour cold water on speculation that his brother is unhappy with his current situation at the club.

'When he’s got his idiot of his brother doing all that stuff - we shouldn’t even be giving his brother the time of day,' Keane asserted. 'Because sometimes you’re just surrounded by idiots, especially in families.

'(But) you come in after the match, and your brother did that... if my brother even done that, you would be looking at him going, “what are you doing?” You would, and do you know what - do you think his brother’s done that without asking him? He’s under contract, probably been paid a decent wage...'

Roy Keane was critical of Mainoo and believed that the player has failed to take his chances

The 20-year-old is behind Bruno Fernandes in the pecking order in the team's starting XI

Ruben Amorim has been unwilling to rely on Mainoo and suggested that he has not taken up opportunities given to him

Keane also highlighted how Mainoo's one outing against Grimsby had not necessarily made a good case for his future inclusion in Amorim's starting XI teams.

'Sometimes, that’s the only chance you get, and you take it,' Keane added.

'If you’re coming back on the bus after Grimsby, and be on that bus as United players, and you’re sitting there and you’re going, “we just lost to f****** Grimsby”, and someone says, “you had that opportunity, you’re not going to get a chance for another six months”, I don’t expect to get another chance! Because I can’t beat Grimsby!'

When podcast co-pundit Jill Scott argued that all of the Man United team to lose to the League Two strugglers had been 'c***', Keane continued: 'When everyone else is terrible, you make sure you’re good.

'Let me tell you, it’s very easy to be good in a bad team, so you rise above that. You know what, we defend the players too well sometimes on here.'

Among the former Man United stars to have defended Mainoo's position at Man United are Paul Scholes, Nicky Butt, and Rio Ferdinand.

All three of the former team-mates have called upon the player to leave the club in January, with Scholes suggesting that he might succeed at Premier League rivals Chelsea .

'You would have to advise him to go,' he stressed last week. 'If he rang me and said "I think Chelsea are in for me what do you think", I'd say "all day long".'

'He is a 20 year old kid, he is going to have to leave. What will happen know is (Amorim will) bring him into a game and he won't be great, because he needs five, six, seven, eight games. He'll throw him into the team and say "I told you so".