IndyCar won't return to Auto Club Speedway in California next season in a move that weakens the series' dwindling presence on oval tracks.
The series confirmed Friday that discussions with track officials couldn't identify a suitable date to return to Fontana.
Although the June race this year was one of the most spectacular IndyCar events in the last several seasons in terms of on-track action, the race was held in front of a crowd of less than 10,000.
Track officials made it clear the June date was not workable, and that IndyCar could only return to the oval as the season finale. Fontana hosted the IndyCar finale from 2012-14, but the races were held in September the first year, October in 2013 and Aug. 30 last year.
IndyCar said it wanted to comply with Fontana's request to be the season finale, but "the two sides were unable to identify a start time and broadcast window that would not adversely impact television viewership on the East Coast."
"There was a tremendous amount of effort put forth to keep Auto Club Speedway on the calendar," said Mark Miles, CEO of Hulman & Co., the parent company of IndyCar. "We mutually agreed that our inability to identify a date for next year doesn't preclude us revisiting these conversations in the future."
IndyCar, which was created as a series that would race on ovals in America, has just six on this year's 16-race schedule. Two of the ovals, Milwaukee and Pocono, could also vanish from the schedule next season because the facilities have struggled to make IndyCar a commercial success.
Pocono, which hosted a July race the last two years, will gauge how next week's race date works out for the track in terms of attendance before deciding on 2016.
Meanwhile, Phoenix International Raceway officials confirmed Friday they are in serious discussions to bring IndyCar back to its oval.
Although a deal has not been reached, an April date has been zeroed in on and this is the closest the track has come to bringing IndyCar back in various discussions over a decade.
Phoenix last hosted IndyCar in 2005, and despite an affinity for the track by both competitors and fans, no return could be worked out.
Miles this year has added a street race in Boston and the road course at Road America in Wisconsin to the 2016 schedule. Road America hosted IndyCar from 1982 through 2007, and the Boston event will be new to the series.