Ferrucci left Dale Coyne Racing after 2020 to move full time to NASCAR, seemingly ending his open wheel racing career. However he was approached by and signed with Rahal Letterman Lanigan Racing to run a third car sponsored by Hyvee at the 2021 Indianapolis 500. Ferucci drove the car to sixth place, the highest of any of the RLL drivers in the race. Ferruci's results at the Indy 500 earned him four additional drives with RLL at Detroit, Mid Ohio, and Nashville. Ferucci expressed to Bobby Rahal that he would be open to a full time return to IndyCar if Rahal were to give him a drive in the third RLL car full time.