DETROIT -- Roger Penske has cancelled the doubleheader race at Detroit and adjusted the IndyCar schedule Monday as the series remains on hold during the COVID-19 pandemic.

Penske told The Associated Press he had no choice but to cancel the two races at Belle Isle because Michigan is under a stay-at-home order and workers cannot begin constructing the track. Penske is the promoter of that race.

"We're under lockdown, we can't do anything,'' Penske said. He had previously told AP he could move the event to later in the season if racing remained on hold by May 30.

IndyCar is now tentatively scheduled to start its season June 6 at Texas Motor Speedway.

Penske closed on his purchase of IndyCar and the Indianapolis Motor Speedway in January but all his plans have been disrupted since the season-opening race was called off 48 hours before the green flag.

To ensure a 15-race schedule, IndyCar will now run doubleheaders at Iowa Speedway, Laguna Speedway in California and return for a second race on the road course at Indianapolis Motor Speedway in October. It is the third schedule revision for the series and Penske has already taken the unprecedented step of moving the Indianapolis 500 to August and off Memorial Day weekend for the first time in race history.

``We're committed to bringing fans as much on-track action as possible,'' Penske Entertainment Corp. President and CEO Mark Miles said. ``Our updated schedule features additional racing at fan favourite venues and adds to the total number of events on our calendar.''

The Iowa 300 weekend will add a Friday race on July 17, along with the previously scheduled race July 18. The Firestone Grand Prix of Monterey will now feature a race Sept. 19 as well as the previously scheduled race Sept. 20.

The series has already cancelled races at Long Beach, California, Barber Motorsports Park in Alabama, Circuit of the Americas in Texas and now Detroit. The race in St. Petersburg, Florida, may still be held as the season finale. It had been scheduled as the March 15 opener and teams were in place preparing to compete without spectators when the escalating coronavirus crisis forced Penske to pull the plug.

``Like our fans, we're disappointed we won't be racing in Detroit this year,'' Miles said. ``However, we're excited to return to Belle Isle in 2021 and know we'll put on a great show for everyone when we do. We also appreciate the flexibility and support of our event promoters at Iowa Speedway and Laguna Seca, who have enthusiastically embraced the opportunity to host doubleheaders.''

The added stop at Indianapolis on Oct. 3 would be the third trip to the speedway in one season for IndyCar. Penske scheduled the Harvest GP is in addition to a July 4 scheduled road course race at the speedway and the Indy 500. The July 4 race is currently scheduled to be part of a doubleheader weekend with NASCAR.

``IndyCar in October at IMS might bring slightly cooler weather but will definitely be warmly embraced by our fans,'' said speedway President Doug Boles. ``We appreciate everyone's support and flexibility as we continue to navigate calendar adjustments caused by the COVID-19 situation.''