McLaren sources at Silverstone say that the plan to run a team in IndyCar has been shelved indefinitely. The team owners have decided that they must concentrate on returning to contention in Formula 1.

The team began the season looking strong, with two double-points finishes for Fernando Alonso and Stoffel Vandoorne in Australia and Bahrain. Recently has found itself slipping backwards in the F1 pecking order.

This is below the team’s expectations and has led to the departure of the team’s racing director, Eric Boullier, and a restructuring of the F1 operations. Part of the logic behind the McLaren-to-IndyCar idea was to cross-sell sponsorships between F1 and IndyCar. Now, however, splitting the effort is not deemed to be sensible, and F1 is the company’s core business.

IndyCar team owner Michael Andretti, said on his visit to F1 in Canada on the June 9-10 weekend that if there was to be a McLaren IndyCar team in 2019, a decision would be required almost immediately, in order to have things properly structured. That was more than a month ago.

There is the additional problem of the Alonso now being a Toyota factory driver in the FIA World Endurance Championship, which would make it problematic (but, apparently not impossible) for him to race with Honda engines at Indianapolis.

Honda and Toyota are famous rivals. Honda motorsport boss Masashi Yamamoto said at the French Grand Prix three weeks ago that he was only an advisor and that the decision will make American Honda. Toyota, on the other hand, is unlikely to want to see its star driver winning for Honda in the United States.

As far as IndyCar CEO Mark Miles is concerned, McLaren has a possibility to join the IndyCar Series in 2019.

McLaren has been quiet in the past few weeks regarding interest in IndyCar. We can expect it after it has focused on getting its Formula 1 team more competitive. Two-time CART champion and 2003 Indianapolis 500 winner Gil de Ferran replaced Boullier as McLaren sporting director on July 4.

Since that time, there has been little talk about McLaren joining IndyCar. Miles said that doesn’t mean they have reached a decision that it won’t happen.

“No. Period.” Miles said. “I think Zak will be straightforward with us and keep us informed. When he has news one way or another we’ll know it.”