McLaren apparently offered engine partner Honda two alternatives early on in the season when it realized where it stood with the Japanese manufacturer.
McLaren's doubts about Honda's 2017 power unit started as far back as pre-season testing in Barcelona in early March.
To try and avoid an engine debacle, the Woking-based outfit took a pro-active stance and came up with several solutions destined to help itself and its partner.
"At the first tests of 2017, we realised serious problems were waiting for us," Boullier revealed in an interview with French weekly Auto Hebdo.
"We began to get nervous and started looking for solutions that could improve the situation.
"As a last resort, we were ready to offer that Honda skips the season while it improves and McLaren would use some other engines for that period."
Boullier did not provide details however about which power unit it would have used if Honda had accepted to take a sabbatical year from F1.
Another alternative was suggested however, and included bringing in outside help to support Honda's efforts.
"Honda engineers and their colleagues from Mercedes could do a technical cooperation," he revealed.
"Or forming our own group of specialists in the engine area made up of different companies to help Honda find more efficient solutions more quickly.
"Unfortunately, none of the proposals were properly explored and as a result we ran out of arguments.
"We had to come to the conclusion that there was no other way out except for the termination of the cooperation," Boullier said.