IndyCar called off two scheduled May races in Detroit on Monday due to the coronavirus pandemic but added second races at Laguna Seca and Iowa and a third Indianapolis event.
The series had already postponed the 104th Indianapolis 500 oval classic from 24 May to 23 August and called off races at Long Beach; Austin, Texas and Alabama due to the deadly virus outbreak.
The Dual in Detroit races set for 30-31 May were canceled as well, leaving the next event on the current schedule as the Genesys 600 on 6 June in Fort Worth, Texas.
The new IndyCar Harvest Grand Prix will be staged 3 October on the same Indianapolis Motor Speedway road course where the Grand Prix of Indianapolis will be contested 4 July after being moved from May.
An original Harvest Classic was staged at Indy in September 1916, the only race at the speedway outside of May from 1911-1993.
Two scheduled events will become doubleheaders with the Iowa 300 on 18 July being joined by another oval race the night before and the Grand Prix of Monterey at California's Laguna Seca road course now having races on 19-20 September.
The revamped series will offer 15 races, two fewer than originally scheduled, with a street race in St. Petersburg, Florida, yet to be rescheduled.
"Our goal is to preserve as much racing competition as possible while prioritizing the health and safety of our participants and spectators," said Penske Entertainment Corporation president Mark Miles.
"The Covid-19 situation continues to be dynamic and challenging for everyone, so we have developed contingency plans which will allow us to respond to changing conditions."