Rahal Letterman Lanigan Racing driver Santino Ferrucci will need to pass a fitness test before rejoining the Indianapolis 500 field tomorrow.

The 22-year-old crashed heavily during Practice 4 this morning and was taken to Methodist Hospital for assessment.

He returned to the Indianapolis Motor Speedway complex soon enough and provided a progress report via social media.

“I’m back at the Speedway, all checked out from the medical,” said Ferrucci.

“I go through a final physical test tomorrow to see if I can get back in the car and drive.

“As you can tell I’m a little sore but I’m happy to be here and the guys are working really hard to make sure the Hy-Vee Honda is back on track and it’s going to be really quick.”

Despite his crash, Ferrucci posted the third fastest time of the session.

In any case, he and RLLR team-mates Graham Rahal and Takuma Sato will not be able to take part in the opening half-hour of Practice 5 as punishment for their part in a collision between Scott McLaughlin and Colton Herta.

Assuming Ferrucci will be declared to continue in the event, he will be one of 35 drivers vying for 33 places in the May 31 (AEST) race.

Practice 5 is due to run from 02:00 to 08:00 AEST on Saturday.