James McClean has apologised for his outburst on Twitter

Republic of Ireland winger James McClean has apologised for his foul-mouthed tweet after the clash against Kazakhstan.

Republic coach Giovanni Trapattoni is aware of McClean's outburst and must now decide what action, if any, to take against the 23-year-old Sunderland player ahead of Tuesday's friendly against Oman at Craven Cottage. The tweet once again raised questions about Trapattoni's relationship with some of his players. Last week Darron Gibson informed Trapattoni he would not be joining up with the squad due to his lingering disappointment at spending the European Championship on the bench. And earlier this summer Kevin Foley refused a call-up to the squad for the Serbia friendly and vowed never to play for Trapattoni again after being overlooked for Euro 2012. Striker Doyle has rubbished claims of disharmony within the squad, though, and insisted all the players remain firmly behind Trapattoni. "Everyone respects the manager and there is no other scenario," Doyle said after scoring last night's winner in the 89th minute. "The atmosphere is the same here as it has been in any Republic squad I've been involved in. "Everyone is entitled to their opinion, but as far as I can see everyone is right behind the manager and hopefully that win will help ease the pressure on us."