Oliver Askew will not be retained by Arrow McLaren SP for 2021, but may still race for the team in the IndyCar finale at St. Petersburg.
Reigning Indy Lights champion Askew had scored a podium at Iowa Speedway and was leading the rookie standings up until the August Indianapolis 500 when he suffered a heavy crash while avoiding an accident.
Although he then raced in the double-headers at Gateway and Mid-Ohio, he reported to the IndyCar Medical Team afterwards that he was suffering from balance issues.
Following tests, he was not cleared to drive at the Harvest Grand Prix double-header at Indianapolis Motor Speedway's road course, where his place was taken by three-time Indy 500 winner Helio Castroneves.
An Arrow McLaren SP statement confirmed that the Florida-born 23-year-old will race for the squad at his 'home' race at St. Petersburg "subject to him being declared fit to race by the IndyCar medical authorities".
Team co-owner Sam Schmidt said: "We believe that Oliver has a great deal of talent and potential for the future.
"He has had an incredibly difficult rookie year, with a lack of overall track time and recent medical issues.
"We want to give Oliver the time to pursue new opportunities for 2021 and the ability to race at St Pete.
"Come the end of the year, we will wish Oliver the very best in all of his future endeavours and he will always be a friend of the team."
Askew's statement read: "It's been a steep learning curve this year but I appreciate all of the experience I have gotten with Arrow McLaren SP.
"I've certainly had to develop very quickly as a driver and I know I have shown my speed and capability when able to this season.
"However, I think it makes sense to pursue the next chapter of my career outside the team.
"I am grateful for all the support I've received from my crew, the team and all the fans. I wish the entire team well in the future."
Aside from his Iowa podium, Askew has only finished in the top 10 on two other occasions this season - a ninth place in the opening event and sixth in the second Iowa contest.