Indy Lights graduate Zachary Claman de Melo will replace the injured Pietro Fittipaldi at this weekend's IndyCar race on the Indianapolis road course.
De Melo and Fittipaldi had been due to split driving duties of the #19 car this season, with the Brazilian slated to drive the Indy road course and the Indianapolis 500.
But the injuries Fittipaldi suffered in a crash during qualifying for the World Endurance Championship season-opener at Spa-Francorchamps has forced DCR to rethink its plans.
It has opted to give De Melo the seat for this weekend, but DCR is currently searching for a stand-in for the Indy 500 and Texas Motor Speedway rounds.
"I'm extremely excited to get to race this weekend aboard the #19 Paysafe car, but I'm sad that it's under these circumstances," said De Melo.
"My thoughts are first and foremost with Pietro, you never want to see that happen to a competitor, much less a team-mate.
"Getting to race at the Indianapolis Motor Speedway is always special.
"I enjoyed racing there in Indy Lights and I can't wait to now get a chance to drive there aboard an Indycar."
Katherine Legge has emerged as an early contender for the Indy 500 drive, although a proliferation of one-off drives for the 2018 race will make finding Fittipaldi's replacement more difficult.
De Melo has not been completely ruled out of continuing for the Indy 500, but team owner Dale Coyne suggested it was looking for a driver with more experience.
Fittipaldi is expected to return to IndyCar for the Mid-Ohio round at the end of July and is heading to Indianapolis for the next stage of his treatment after he leaves Belgian hospital.