Former Manor F1 driver Rossi moves to IndyCar with Andretti

The American was battling for an F1 seat with Manor this term, after contesting five grands prix with the team in 2015, but missed out to Rio Haryanto last week.

Rossi will drive the No.98 Honda and get his first chance in the car when he takes part in a rookie test day at Sebring on Tuesday.

"I'm very much looking forward to making my IndyCar Series debut this season and am proud to be racing with a team of such high calibre and pedigree as that of Andretti Autosport," said Rossi, pictured having a seat-fitting with the team.

"As a racer through and through, I cannot wait to get started; our goal is to be competitive immediately at the first race in St. Petersburg."

Before securing his GP2 seat with Racing Engineering - eventually finishing second to Stoffel Vandoorne - Rossi was close to switching to IndyCar in 2015 with Dale Coyne Racing.

Rossi joins Marco Andretti, Ryan Hunter-Reay and Carlos Munoz at Andretti Autosport after the team merged with Bryan Herta Autosport.

Former Toro Rosso F1 driver Scott Speed races for the Andretti outfit's Global Rallycross arm.

"We're really excited to have Alexander join the team," said Andretti Autosport CEO Michael Andretti.

"His credentials speak for his ability and we're confident he'll transition seamlessly into IndyCar racing.

"It's neat to have the last three American F1 drivers in 25 years to be under one roof, I think it speaks to the level of talent we have."

Autosport understands Rossi has not given up on hopes of earning a full-time race drive in Formula 1 and will continue to assess his options for 2017.

The 2016 IndyCar season starts in St Petersburg on March 13.