Michael Carrick has insisted he does not doubt Lisandro Martinez’s commitment to Manchester United – even after the defender launched a verbal attack on sporting director Jason Wilcox and was then sent off in Saturday’s defeat to Chelsea.

The Argentinian, who apologised after criticising Wilcox and United’s recruitment following the loss to Atletico Madrid, has been at fault for a series of goals in recent weeks and his red card at Stamford Bridge condemned Carrick’s team to a third consecutive setback.

Martinez elbowed Chelsea defender Wesley Fofana to concede a penalty, which Cole Palmer scored, and collect his second yellow card, meaning he will be suspended for Sunday’s game against Aston Villa.

The Argentina international is out of contract in the summer, though United have the option to extend his deal for a further year.

But Carrick was adamant he was not questioning the defender’s attitude, saying: “I've got no concerns about commitment at all. Things happen in football. Sometimes you do things, sometimes you make a decision, sometimes you make mistakes, sometimes goes well for you. But the commitment is not an issue for sure.”

Captain Bruno Fernandes has also given an explosive post-match interview recently, criticising Carrick’s tactics after the 4-1 loss to Como.

But Carrick said he is not worried about the image that his squad lack discipline, adding: “The dressing room is a good, good place, so perceptions are a funny thing. They can they can they can make things look all sorts of different ways and think about all sorts of different things. The commitment of the players to the club, to me, to each other – I don't question that at all. We need to play better, we can make better decisions, but commitment's not a thing at all.”

United face Roma in the Champions League on Tuesday with the under-pressure Carrick claiming he can’t wait for the match.

“You might think I'm crazy with the results we've had and what's going on, but I'm genuinely, really can't wait for the game,” he said.

United will again be without Patrick Dorgu and Luke Shaw. The England left-back will be out until the international break but the Denmark international is back in training, though he will not be involved against Roma.

Carrick is waiting to see when forward Marcus Rashford is fit to return. “We'll just have to see day by day how he keeps improving,” he added.