Carlos Huertas has signed an 11th-hour deal to become the driver of Dale Coyne Racing's second car in IndyCar.
The Colombian, who tested with Panther Racing during the off-season, admitted that he will be disadvantaged by having missed the recent open test at Barber, but said that he hopes to get up to speed quickly.
"It would have been better to do the open test, but the good thing is that nobody has tested here [in St Petersburg]," he said.
"[Team-mate Justin Wilson] is one of the main reasons I wanted to come here because he's really fast and good on road courses and ovals.
"We need somebody to push me along, and I'll listen to all he has to say."
Huertas' confirmation takes the count of full-time rookies on this year's IndyCar grid to four, placing him in a group that also includes Mikhail Aleshin (Schmidt Peterson Motorsport), Carlos Munoz (Andretti Autosport) and Jack Hawksworth )Bryan Herta Autosport).