All options are on the table in order to return McLaren to the front of the grid in 2018, according to the team's executive director Zak Brown.

After six rounds of the 2017 season, McLaren sits rock bottom in the constructors' championship with zero points. For a third year running, the performance and reliability of the car's Honda power unit has been the team's biggest weakness and rumours of a switch to Mercedes power resurfaced as recently as the Spanish Grand Prix.

The team's lack of competitiveness this year led to a deal for star driver Fernando Alonso to skip the Monaco Grand Prix and take part in the Indy 500, but with that adventure also ending with a Honda engine failure, the reality of the team's issues in Formula One are back at the fore. Speaking in Indianapolis on Sunday, Brown highlighted Honda's power unit as a "substantial" issue and said all options were being considered to turn the team's fortunes around next season.

Dan Istitene/Getty Images

"We've got to work through our issues and our issues are substantial in the back of the car," Brown said. "2018 is not far away, so we are going to have to evaluate how we get to the front of the field, and as Jonathan Neale my partner in racing [and McLaren COO] has said, all options are on the table and we have to get back to the front. We're not quite sure how we are going to do that, but we are working on it."

Alonso has already made clear that his main priority is to find a winning car in 2018 and that he will show no allegiance to McLaren if it is unable to deliver. Brown says McLaren has until the summer break to prove it is a viable option for the two-time world champion next season.

"Certainly sitting here right now it looks very difficult imagining us running for the world championship next year. But you can make big progress. We're trying to figure out how to get ourselves in that position and we've got a little bit of time before the summer break.

Jared C. Tilton/Getty Images

"Let's see how the next few months go. And I don't know about convincing Fernando, he's going to convince himself whether he feels it's an environment he wants to race in. I think we'll let Fernando and the race team do the talking and see how we are in the second half of the year."