Jack Hawksworth has been ruled out of this weekend's race at Pocono Raceway after being diagnosed with a myocardial contusion following a hard crash in turn 1 midway through the second practice session on Saturday afternoon.

Hawksworth had been able to climb out of the wrecked Bryan Herta Autosport #98 but was seen to be limping his way to the medical car. He was checked out by the in-field care centre and initially appeared to have suffered nothing more serious than a bruised left knee.

"I'm fine, just a little bit sore," he'd said immediately after the accident. "I think I'll be cleared to drive so that's not a problem."

However Hawksworth subsequently complained of feeling unwell, and as a precaution was dispatched to the nearby Lehigh Valley Health Network in Allentown, Pennsylvania for further tests and evaluation.

That determined that he had suffered bruising to the heart muscle during the crash impact. The hospital kept him in overnight for observation as a precaution.

IndyCar Medical Director Dr Michael Olinger announced on Sunday morning that Hawksworth was no longer medically cleared to drive this weekend, and that he would need to be reevaluated by the medical team before he could take part in next weekend's race at Iowa Speedway.

Hawksworth previously crashed during practice for the Indianapolis 500 in May, but he admitted to reporters on Saturday that his latest crash at Pocono "was a much harder hit."

"I went into 1 and I'd been pushing and understeering through there and went in there this time and just got loose and went into the wall," he told reporters immediate after the incident. "It happened very quickly and just snapped. I went in there quickly and it hit the wall.

"We'd been understeering in turn 1 during the whole session and there's a tail wind going into there so we'd been pushing a lot," he continued. "We just put tyres on and went into 1 and picked up a big oversteer instead of the understeer and it took us out and I went into the wall. If I thought I was going to stick it into the wall, I would have thought it would be on turn 3, but it was turn 1."

The #98 was heavily damaged in the accident. Even if Hawksworth had been uninjured and able to carry on with his participation, the car was certainly in no fit state to take part in Saturday's qualifying session.

Even knowing that the best that they could hope for was a back row start, the team carried on working on rebuilding the car for Sunday's race until the news was confirmed that Hawksworth would not be returning to the track. The team is not expected to seek a last-minute replacement driver to stand in for the 23-year-old Englishman.