Formula One drivers met in Magny-Cours on Friday to discuss their role in the US Grand Prix fiasco.
Fourteen drivers and seven teams were advised to pull out of the race due to safety concerns over Michelin tyres.
Although most of the drivers signed a letter broadly in support of the teams that pulled out, five drivers, including Michael Schumacher, did not.
"I don't understand the situation and I will try to understand it better at the meeting," said Toyota's Jarno Trulli.
Rubens Barrichello, Tiago Monteiro, Narain Karthikeyan and Robert Doornbos were the other drivers that did not sign the letter.
The meeting will try and discover why they did not join their counterparts despite claims that they were asked to.
"The situation is not clear. I think we will be more weak because I received the document direct from the Grand Prix Drivers' Association," added Trulli.
"We all know how many people are in the GPDA and probably most of us here are GPDA members.
"We all get the information from the GPDA by e-mail so nobody can say they didn't get the message.
"They can only say they didn't agree. That is my opinion but I think it is better to discuss it more."
However, Schumacher says the GPDA were not involved in the process of preparing the letter.
"Just to make clear, this was not a GPDA thing. I think we just have different opinions about it, which is only natural so I would not have signed it," he said.
"The GPDA was not involved in that one because it has nothing to do with circuit safety.
"Here it is a mechanical situation, from one team to another, which is not a subject matter for the GPDA to get involved in.
"As far as I understand, it was an initiative from Renault. I don't recall they called me."
The seven teams that pulled out of the race, Renault, McLaren, Toyota, Williams, Sauber, BAR and Red Bull, were found guilty on two charges by motorsport's governing body.
However six of the teams say they will appeal, with Red Bull still considering their options.