Double Formula 1 world Fernando Alonso will be "open" to offers from other F1 teams for 2018, he has said.

The Spaniard, who is out of contract with McLaren at the end of the year, has insisted it will be the summer break before any kind of attention will switch to next season.

However, ahead of his home race in Barcelona, the question of his future is among many have for the 35-year-old.

"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 was quoted by F1i.com.

He also emphasised how his upcoming appearance in the Indy 500 was as much about a break from McLaren's ongoing engine woes as it was about his desire to complete motorsport's 'Triple Crown'.

"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 claimed.

"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."

On the ongoing problems at the British team, Alonso admitted the next stretch of seven races in 11 weeks will be important as he builds toward contemplating his options. 

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

"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," he concluded.