JR Hildebrand, who came within a few hundred yards of winning the Indianapolis 500 as a rookie in 2011, lost his ride with the Panther Racing team after another accident in this year's Indy 500.
In its announcement Thursday, Panther said it parted with the driver by "mutual agreement" and did not elaborate on why.
But Hildebrand's departure came four days after the 25-year-old Sausalito native crashed on the fourth lap of the 200-lap race at the Indianapolis Motor Speedway, leaving him with a last-place finish in the 33-car field.
"JR is a great young man, a class act and somebody who has been a great representative of our race team and all of our partners," Panther Managing Partner John Barnes said in a statement.
In the same release, Hildebrand thanked Panther for the opportunity to drive its car and said he was "looking forward to the next chapter in my IndyCar career."
Panther later said Ryan Briscoe would take over its No. 4 race car this weekend at the Belle Isle street course in Detroit, where the Izod IndyCar Series will hold a doubleheader weekend with separate races Saturday and Sunday.
In 2011, Hildebrand was leading the Indy 500 on the last lap when he crashed into the wall while maneuvering throuugh Turn 4, enabling the late Dan Wheldon to sweep by him for the victory.
Hildebrand's second-place finish in that race was his highest to date in the IndyCar series.