Roy Keane has slammed Manchester United's "crybabies" and wished manager Jose Mourinho good luck amid reports of player unrest at Old Trafford.
Mourinho is under increasing pressure following four matches without a victory while there is mounting speculation over a dressing-room rift – star midfielder Paul Pogba, and his relationship with the United boss, at the centre of it all.
There has been ongoing talk of a row between Mourinho and Pogba, with speculation increasing following a training-ground confrontation last week and the latter being stripped of vice-captaincy duties.
Pogba then claimed he was banned from talking to the media following Tuesday's stalemate against Valencia in the Champions League, while captain Antonio Valencia issued an apology after liking a post on Instagram that called for United to sack Mourinho.
United are already nine points off the pace in the Premier League and former captain Keane demanded the squad give their all on the pitch in a scathing assessment of the situation in Manchester.
"We talk about footballers and managers, not every player is going to get on with the manager, the manager is not going to like every player," Keane told Notts TV. "But what you do as a footballer, and whatever disagreements I've had with one or two managers, when you cross that line, you play for your team.
"I don't care what fallout you've had with your manager, I don't care if you've been at each other's throats, because that is part of the industry, people do fall out. It happens in other industries, but unfortunately when you're Man United – one of the biggest clubs in the world – things will get exaggerated.
"But if you're a footballer for Manchester United and you put that jersey on and you walk out and you don't give 100 per cent because you might be upset with somebody, then, no, good luck to Mourinho."
Asked if he was talking about Pogba, Keane said: "I'm talking about players in general. Players who get upset with a manager, or a coaching staff, and think I'm not going to train properly because somebody upset me, there's a lot of crybabies out there, lots of crybabies.
"When you walk out on that pitch, you're playing for your pride, you're playing for your family, you're playing for your city, whatever it may be. Don't get that worried about what the manager said about you or the coaching staff. You get out there and play.
"You can fall out after the match, but when the game's going on, liven up, play with pride, play with energy, play with spirit. Hopefully play with a bit of a skill, but you can't always play with skill, you can have a bad day, but on your bad days you roll up your sleeves and you fight for that jersey and don't get distracted by the balloons out there."