The Italian tactician has justified his exclusion of the former Reading striker on the grounds that he had been struggling for form at club level
The Wolves front man, who has 53 caps for the Boys in Green, was included in the provisional panel before being demoted to the stand by list for the World Cup qualifiers on March 22 and 26.
"He was not in his team," Trapattoni told reporters. "He could have gone to other teams and it didn't happen.
"It hasn't been a particularly happy time in terms of what he has been through at his club and also with his fitness. I wish to help him but maybe he needs to change clubs."
The Italian tactician also emphasised the importance of LA Galaxy striker Robbie Keane, Ireland's record goalscorer, in the forthcoming games.
"He is our captain," he said. "Usually, I repeat to you, in this international game, the name and the experience is important.
"To the opponent, he's always Robbie Keane. We need that personality on the pitch. And it's not only the name - Robbie also scores goals."
As yet, doubts remain as to the fitness of Keane's potential strike-partner Shane Long and centre back Sean St Ledger, with the Ireland boss uncertain about whether either player will start against Sweden on Friday, March 22.
Meanwhile, Trapattoni has also quashed speculation that he had been offered the role of manager at French club Montpellier, stressing his commitment to Ireland and his desire to qualify for the World Cup in Brazil.
"I don't read this," he said. "I am happy to be here. Happy to go with Ireland to the World Cup in Brazil. I can't stop your rumours as you write the newspapers.
"What can I do against rumours, you need rumours. For me, rumours is unbelievable. I am happy to be here and I wish to achieve this qualifying. Going to Brazil. That would be fantastic. I was there 30 years ago, playing against Pele," added the Ireland boss.