Forsythe have decided to retain substitute driver Oriol Servia alongside Paul Tracy when the injured Canadian returns at Portland next month.
Servia began 2007 without a ride but was called up at short notice when Tracy hurt his back in a practice crash at Long Beach.
The Spaniard proceeded to come from 14th on the grid to second in the race, and then took fourth at Houston a week later.
He replaces Mario Dominguez in the second Forsythe car. The Mexican made a surprise return to Forsythe after being sacked in early 2006, but only managed one top six finish in the first three rounds.
"It's another good opportunity for me," said Servia. "I want to thank Jerry Forsythe and the Forsythe team for putting their trust in me and letting me get back behind the wheel of one of their cars."
Tracy has now been cleared to return to the cockpit and will be back in action in testing at Mont Tremblant later this week.
"It feels good to be back in shape and ready to drive," he said.
"It's been very frustrating, we started the year with a strong result in Vegas and we knew we were starting to build momentum but this injury completely interrupted our plans for the championship.
"It's going to be tough obviously coming from behind in the points but all we can do is go out there, win races, collect as many points as we can and see what happens."