Fernando Alonso might retire from Formula 1 unless the McLaren-Honda package is good enough to fight in front, according to his former teammate Felipe Massa.
But McLaren's season has been tough so far, with the team running at the back of the field and not having scored a point in four races.
Massa, who was Alonso's teammate at Ferrari for four years, is not sure the Spaniard has the patience to wait a long time for success.
"Alonso is not an easy person. He needs results," Massa told UOL Esporte.
"He has a personality of wanting only to be in front.
"This year he will endure working with the team, but if next year things do not change, he could think again.
"I don't know what he would do. Maybe he would end his career."
Massa said he expected Honda to start its McLaren collaboration more competitively, given the behind-the-scenes work that went on throughout 2014.
"But it was also clear that it would not be easy for them," he added.
"The new regulations are very complicated and it takes a bit of time, just as it did for Ferrari and Renault.
"Honda is a year behind those teams but they will improve and have a more competitive time in 2016."