Furious United without Nani for Cup crunch

Nani will miss Manchester United's FA Cup sixth-round tie with Arsenal on Saturday, with his club so angered that Jamie Carragher was refused entry to their dressing room to apologise for his tackle on Sunday.

Such was the ferocity of the Liverpool player's challenge that the gash to Nani's right calf cut right through to the bone. Nani was able to leave Anfield on Sunday evening without the aid of crutches but the wound created by Carragher's challenge is of a depth that will take time to heal, and Nani may now be absent until the trip to West Ham on 2 April.

Nani remains in close contact with his former teammate Cristiano Ronaldo and has already spoken to him twice about the injury - on Sunday and yesterday. Yesterday, he told the Real Madrid player the incident had strengthened his resolve to secure the PFA Player of the year trophy, though there are doubts that Nani will be back before the international break.

The FA confirmed yesterday that Carragher will not face any retrospective action because Phil Dowd has concluded that he stands by his original decision to dispense only a yellow card for the challenge – just as Mark Clattenburg did after Wayne Rooney's elbow on Wigan's James McCarthy a week earlier.

Sir Alex Ferguson's decision to impose a media black-out after Sunday's game appears to have been based in part on a realisation that he would be asked to comment on a refereeing decision once again and with an improper conduct case looming in the next few weeks he is reluctant to worsen his position, having denied the charge. Instead, Ferguson may seek to use what United perceive as another injustice in support of his own case. His decision not to appear after the 3-1 defeat to Liverpool has certainly allowed the events of the afternoon to speak for themselves. There was astonishment yesterday in Nani's native Portugal that Carragher should have been allowed to escape with a yellow card for the challenge. An image of the base of Nani's torn right shin featured prominently across the continent.

The loss of Nani for Arsenal's visit is a bad blow for a United manager for whom Antonio Valencia is still several weeks off a return and Ryan Giggs may be the only fit natural wide player. Ji-Sung Park may come back into contention, having been put through a late fitness test 24 hours before the Liverpool game yet judged unfit to return after his hamstring trouble. But Park does not offer invention and United's lack of it was self-evident against Liverpool. A third consecutive defeat on Saturday would generate intense pressure ahead of Marseilles' arrival in a Champions League last-16 tie delicately balanced at 0-0.

Ferguson, whose improper conduct charge came for his comments about Martin Atkinson's refereeing of last week's Chelsea game and his decision not to dismiss central defender David Luiz, may be surprised to learn that he has some support in Portugal for his view that Luiz, signed from Benfica for £21.5m, deserved to be dismissed in United's 2-1 defeat. The Benfica coach Jorge Jesus telephoned Luiz after the game to say that his performance in the high-profile fixture was not the way he had taught him to play the game.