While Mazda has yet to formally announce its line-ups for the 2020 IMSA season, Andretti Autosports IndyCar driver Hunter-Reay is listed as part of the roster for the Team Joest-run squad for this week's Roar Before the 24 test.
He joins Jonathan Bomarito and Harry Tincknell in the #55 Mazda RT24-P, having subbed for Tincknell in this year's Mid-Ohio race.
The 2012 IndyCar Series champion and 2014 Indianapolis 500 winner last contested the Florida classic in 2018 with Wayne Taylor Racing alongside Renger van der Zande and Jordan Taylor. He finished second overall in the team's Corvette DP in 2013.
Oliver Jarvis, Tristan Nunez and Olivier Pla are set to drive the sister #77 car, in what appears to be an unchanged full-season line-up for the Japanese manufacturer.
Pla was one of Mazda's two extra drivers for the Michelin Endurance Cup races last year along with Timo Bernhard, who this month announced his retirement from top-line racing. DTM champion Rene Rast was also part of the team's Rolex 24 assault.
#77 Mazda Team Joest Mazda DPi: Oliver Jarvis, Tristan Nunez, Timo Bernhard
Elsewhere on the Roar test entry list, Tristan Vautier is listed in both of JDC-Miller MotorSports' Cadillac DPi-V.Rs. The Frenchman contested the full season in the #85 Caddy this year but has not been part of any of the team's 2020 driver announcements so far.
#96 Turner Motorsport BMW M6 GT3: Bill Auberlen, Robby Foley, Dillon Machavern