The 40-year-old, who won on only this fourth start for the team at Long Beach in 2010, went on to score 14 more wins including the 2014 Indianapolis 500, and also won the championship in 2012.
However, after two winless seasons – three should he not triumph in final events of this year’s campaign at Laguna Seca or Long Beach – the team will bid him farewell.
His best result so far in 2021 has been a fourth place at Nashville, while Hunter-Reay only managed a solitary podium last year as he finished 10th in the final standings.
“What started as three races in 2010 grew to over a decade of successes,” said an Andretti Autosport statement.
“Through 12 seasons, Andretti Autosport, DHL and Ryan Hunter-Reay climbed mountains. We claimed a championship and captured victory on racing’s biggest stage. And now, over the next two weekends, Ryan will turn his last laps as our IndyCar team-mate.
“Thank you, Ryan, for 12 great seasons with us: 15 wins together, an Indy 500 victory and an IndyCar title.
“Always a champion, always a friend. Wishing you the best of luck in the laps ahead.”
Hunter-Reay said on Twitter: “This team is and has been like family. Twelve seasons, some of the best memories and accomplishments of my life. Team-mates that have become some of my best friends and thankful for Michael Andretti giving me a shot way back when. Checked off all the major boxes. Onward!”
Ryan Hunter-Reay, Andretti Autosport Honda
Photo by: Michael L. Levitt / Motorsport Images
Writing on Twitter, Andretti Autosport stablemate Alexander Rossi labelled Hunter-Reay as “without a doubt, the best team-mate I’ve ever had”.
“We’ve been through a lot together the past six years so I’ll miss having him at the team,” he said.
“That said, I know we will be seeing him around and I personally plan on being at his house and on his yacht a lot this winter.”
Fellow Andretti driver Colton Herta also paid tribute to Hunter Reay.
“What an honour it’s been to have Ryan as a teammate for the last three years,” he wrote on Twitter.
“His insight and feedback helped me so much. Sad to see him leave but was happy I got the opportunity to know and learn from him!”
Hunter-Reay is believed to be in the running for drives at three IndyCar teams next season, including as a road/street/Indy 500 driver in the #20 Ed Carpenter Racing machine, which is one of his favoured options.
However, Autosport understands that Indy Lights points leader David Malukas, Oliver Askew and current incumbent Conor Daly remain three of Carpenter’s other options.
Romain Grosjean is expected to be confirmed as taking Hunter-Reay’s place at Andretti within the next 10 days, while Indy Lights graduate Devlin DeFrancesco will be named as replacement for James Hinchcliffe.