Gibson has two caps and was not even in the initial squad for the World Cup qualifier.
Trapattoni said: “You have to change. When the water is still in the summer, it stagnates and smells, so you have to change.
“I am happy because I have three or four or five more good players in the squad.
“Now if we have injuries or a red card, I can breathe again because I can think about two or three options.
“I hope Robbie (Keane) plays always, but I don’t know, a red card or an injury…
“But we have others now. Until last week or a month ago, I didn’t know about other strikers.
“At the moment, we have 25, maybe 28 good players.”