After what was an initial part-time deal with Andretti Autosport in 2010, Ryan Hunter-Reay will depart the team after 12 seasons together.
Their partnership yielded the 2012 IndyCar Series title, 15 wins including the 2014 Indianapolis 500, 43 podiums and five pole positions.
The 40-year old has yet to reveal his future plans beyond 2021.