Fernando Alonso is not ruling out staying at McLaren beyond the end of his 2017 contract.

Many people see the works Honda-powered team's ongoing crisis, and Alonso's decision to skip Monaco in favour of the Indy 500, as a clear sign that his patience with the Anglo-Japanese collaboration is up.

Asked what is keeping him at McLaren-Honda now, the Spaniard told EFE news agency: "The team."

He does not rule out staying in 2018, but he said that McLaren would have to be "in a position to fight for the world championship".

"I am hopeful that things will improve, but from September or October I will be open to any kind of negotiation, whether with McLaren or any other team," Alonso added.

When asked about the Indy 500, he sounded unapologetic about skipping Monaco later this month.

"What is clear is that we all need a joy, a result, something, since there is a minimal possibility of winning something here. And it has aroused a huge interest," he said.

"For now we are uncompetitive and unreliable but the year is long, we can do important steps and improvements. I still hope to be happy in the second half of the year."

Alonso revealed that Honda have explained in detail where they intend to make improvements.

"The team is putting everything behind them, because it's not used to being behind so they're putting all the resources needed to help Honda," he added.

"There is a series of races in July but after the summer there will be enough time to analyse what has improved in the team, how is the evolution, to see if the team's curve is flat, up or down, and that will be the moment to see what I will do next year.

"But I will be in F1."

The two-time world champion has yet to pick up a point in this year's championship.