Fernando Alonso says he will "talk to anyone" about a 2018 Formula 1 drive if it does not look like McLaren will be in a position to win races.
The two-time champion's contract with McLaren concludes at the end of this year, and Alonso has made it clear he wants to have a competitive car as soon as possible.
Alonso rejoined McLaren in 2015, but has endured a disappointing spell so far as Honda's engine programme has failed to deliver what the team expected.
The 35-year-old insists his priority is to remain in F1, but warned that he may look elsewhere if McLaren-Honda does not make enough progress soon.
"I like this F1," he said of the new breed of machinery.
"My intention or first priority is to race here. I am happy with the team but we are not winning.
"If from here to September/October we are in a position where we see clearly a possibility to win in 2018, I will be more than happy to stay with the team.
"If it is not the case then I will be more than happy to talk to anyone."
Alonso will miss the next F1 race in Monaco to contest the Indianapolis 500, and said he is likely to make a decision about his future after summer.
"I will have to think a little bit after the summer as now it's not an easy period [coming up] and with the Indy 500 thing will be difficult to think about something else," Alonso said.
"Around the summer I need to consider what I will do next year and if it is time to find other challenges outside F1 or if in F1 there will be an opportunity to win the championship, which is my main goal.
"I am very open to anything."
After team-mate Stoffel Vandoorne failed to start the Bahrain Grand Prix, Alonso was dealt the same hand by another engine problem in Russia a fortnight ago.
Ahead of his home grand prix, the Spaniard reiterated his belief that Honda's reliability has been "unacceptable" so far in 2017.
"We need to raise our game and hopefully finish with both cars this weekend," he said.
"We have been underperforming in the first four races and we didn't finish any of the GPs yet, in my case.
"Not being able to start the race with Stoffel's car in Bahrain with my side of the garage in Russia, completely unacceptable.
"We need to raise our game here in terms of reliability and hopefully finish with both cars.
"Hopefully this is the start of a new championship for us."