Zak Brown says McLaren is deciding whether to enter a full two-car team in the Indycar series in 2020 or 2021.

"There is no doubt that the shareholders at McLaren would like to be in Indycar. I think it's more of a when than an if," he said.

Brown, who is McLaren's team boss, skipped the Chinese grand prix last weekend and instead attended the Indycar race at Long Beach.

Gil de Ferran ran the team on his behalf in Shanghai.

"Gil is in China," Brown said, "but as soon as he comes back from China, he'll then start focusing on Indianapolis."

Brown is referring to the Indy 500, which Fernando Alonso will tackle for the second time next month.

But Brown says the 2019 challenge is different.

"2017 was easy because Michael (Andretti) did the majority of the work and has got a lot of experience. This is a totally different experience. This is a full McLaren effort," he said.

Indeed, former Force India boss Bob Fernley is running McLaren's Indycar programme, and Brown said a full-time team for the full series is on the cards.

"It's a place that McLaren would like to race," he said.

"We've been very focused on formula one, and we remain very focused on formula one. If we were to do it (Indycar) for 2020, we'd need to make that decision in the summer.

"So it's nothing that we've ruled out for 2020, but if not then, we'll look towards 2021."

When asked if Alonso is central to McLaren's Indycar plans, Brown answered: "No." Indeed, the Spaniard is not ruling out a return to F1 for 2020.