Speculation over the respective futures of Jenson Button and Kevin Magnussen has been rife and Fernando Alonso has been linked with a return to the Woking-based team as he prepares to leave Ferrari.
Team principal Boullier has vowed to take his time over such a key decision as he attempts to make McLaren a force in Formula One once again.
"There is still no decision yet." he said in an exclusive interview with the official Formula One website.
"I will not tell you much about this - just this much: we need a mix of experience and eagerness.
"In this time of recovery for McLaren I need a boost, so our driver line-up needs to be boosting the team's morale and team's determination to reach as quickly as possible the level where we should be.
"I always said that we are working on the strategy for the coming years - plural - which means we could take on a big name now, or even two big names for next year, or we could stay the same and go for a big name - or again two big names - for 2016.
"We are still assessing what we should do, as it is a big decision that will obviously be driving our success for the medium term. If we take the wrong decision we could be successful in the short term but maybe not in the long term.
"And we are in the comfortable position of being able to wait. I know that doesn't make it comfortable for Jenson (Button) and Kevin (Magnussen), but I have to think about McLaren first. We have to make sure we make the right decision."
McLaren are fifth in the constructors' championship with three races remaining this season.