Republic of Ireland scrape a 0-0 draw in Hungary as manager is left unhappy at way team coped with tactics.
Euro 2012: Ireland may redraw plans after Trapattoni unhappy with performance
The Italian had previously claimed the line-up which faced Hungary in a warm-up friendly last night would be the same which would take on Slaven Bilic's side in Group C on Sunday.
But Trapattoni was left unhappy at the way his team struggled with the Hungarians' 4-2-3-1 format, and allowed midfielder Balazs Dzsudzsak to roam behind lone striker Adam Szalai.
Afterwards he said: "I have to show the team what happened this evening because it is my duty and we need to change.
"We must understand why. I know why, I knew before why, yesterday and the day before.
"When we meet a team with one striker, I know that between two lines, we are in difficulty.
"To have a balance, we have to give up one striker or put one more in midfield.
"In the past, I know this position, I know this line-up. I will speak with the team and I will show them our difficulty because we need to take a decision to sacrifice a striker, or we need to change the situation."
Trapattoni has set great store by the 4-4-2 system he has employed during his four years in charge of Ireland, but he is desperate to find the flexibility to be able to adapt to different formations when the need arises.
He said: "We need one more in midfield. If you watch, if you see, one more in midfield. It is clear."
The veteran manager admitted Ireland had been fortunate to extend their unbeaten run to 14 games after the 0-0 draw at the Ferenc Puskas Stadium.
They emerged from a tight encounter with their clean sheet intact, but only just as Shay Given proved his fitness with a fine first-half display before Keiren Westwood took up the baton after the break.
Fellow injury doubt John O'Shea also proved his fitness for the tournament, playing the full 90 minutes to prepare him for the match in Poznan.
Given's departure at the break in his first appearance since recovering from a knee injury raised eyebrows, but Trapattoni was happy with what he had seen.
The Italian said: "I think this evening, we have been a bit lucky because in the first half, the opponent deserved to score a minimum of two goals."