Galbusera has worked alongside Rossi since the 2014 campaign, after the Italian rider parted ways with long-time chief mechanic Jerry Burgess.
But now Rossi is set to have a third different crew chief for 2020 as he bids to return to competitiveness and end a winless streak dating back to the 2017 Dutch TT.
Davide Munoz has emerged as the favourite for the job, with Spanish publication AS having identified him as Galbusera’s likely replacement.
Munoz currently works alongside Rossi protégé Nicolo Bulega in Moto2 at the VR46 team, and guided Pramac Ducati rider Francesco Bagnaia to last year’s intermediate class title.
The 41-year-old Spaniard has previously worked with the likes of Pablo Nieto – now the boss of the VR46 operation – and Rossi’s current teammate Maverick Vinales.
Rossi has been off the podium since April’s Austin race and heads into the final five races of the current campaign sixth in the standings, 10 points behind Vinales.