Conor Daly is on standby for Dale Coyne Racing after IndyCar regular Jack Harvey withdrew from the first leg of the Iowa Speedway double-header.

Harvey has been battling neck and back spasms for more than a week and struggled through the Mid-Ohio round.

The British driver had planned to sit out Sunday’s race at Iowa Speedway and injury sub Daly was poised to take the reins of the #18 car but was stonewalled by IndyCar.

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Because he failed to participate in practice or qualifying and there was insufficient time to complete a shakedown prior to the race, Daly could not race.

Despite being visibly in pain after his qualifying runs, Harvey was forced to drive.

However, he withdrew just 28 laps into the race.

“In truth, we pretty much made the decision that we were hoping Conor was going to be able to drive,” Harvey said on Stan Sport’s coverage.

“I have a lot of respect for IndyCar, but they didn’t clear him to drive today without doing any practice sessions or qualifying or anything like that.

“That forced our hand a little bit. It basically meant we had to start the race to try get some leaders’ circle points.

“I would say I’m a very lucky person to get to do this for a job but it’s agony in the car. I can’t really describe that pain.

“We actually probably did more laps than what I thought we might.

“The competitive person that everyone is who does this, it splits your spirit to the core knowing that you can’t do it.

“Everybody on the IndyCar medical side have been fantastic. It was their recommendation not to do it.

“I’ve got a lot of respect for Dale [Coyne] and everybody at Dale Coyne Racing so I still wanted to do my part.

“Under safety car, under caution laps, it really hurts.

“I hope people have enough respect for me when I say it hurts it isn’t just like ‘Oh, it’s a little bit of pain’, I’ve tried pushing through this two weeks now and I just can’t.”

It’s expected Harvey will miss Monday’s race, which is scheduled to start at 2am AEST.