The 23-year-old was included in Trapattoni’s squad that travelled to Kazakhstan on Friday, but the Sunderland winger did not make an appearance as Ireland came from behind to win 2-1.
Following their opening 2014 World Cup qualifier, the former Derry City midfielder expressed his disgust at not featuring against Kazakhstan despite Ireland trailing for 87 minutes of the tie.
He wrote on Twitter after the game: “Delighted as a fan we got the win. Personal level #fuming #f**kinjoke #embarrassing.”
McClean has since apologised for the post ahead of Ireland’s friendly against Oman at Craven Cottage on Tuesday, and Trapattoni said the youngster was lucky not to receive his marching orders.
“Another manager, English or German, would have said take your bag and go home, but I might need him in the game to score a goal,” Trapattoni said.
“He was mortified [when he was pulled up in front of the squad]. If he could have, he would have eaten his words. He was very apologetic.
“I said to everyone this is not about respect for the manager, this is about respect for everyone. I said the players are your colleagues.
“If I don’t play him, I can play others. There was Stephen Kelly and Kevin Doyle on the bench. They have many caps.
“The matter is closed now. With the young we need to have patience.
“Sometimes they say things they regret.”