The Spaniard fractured his humerus in the season-opening Spanish Grand Prix in Jerez last month and had to undergo a second operation after damaging a plate in his arm while opening a window ahead of the second race in Jerez.
Marquez, 27, has missed three races due to the injury, and the Styrian Grand Prix on Sunday will be the fourth he sits out.
"All parties have decided to modify the planned recovery process," Repsol Honda said in a statement.
Motorcycling
Rossi announces decision to retire at end of season
05/08/2021 AT 14:45
"The objective of both Marquez and the Repsol Honda Team is to return to the world championship when Marc’s arm has fully recovered from the serious injury that occurred in Jerez.
"It is estimated it will take between two to three months before Marc can return to the RC213V."
Honda have not set a return date for Marquez, who is now unlikely to be back until late in the 2020 season.
Six-times MotoGP champion Marquez has yet to score a point this season and is 67 points behind Petronas Yamaha's Championship leader Fabio Quartararo.

Watch Danny Buchan secure pole position at Snetterton

Motorcycling
MotoGP star Jason Dupasquier dies after crash
30/05/2021 AT 11:01
Motorcycling
Quartararo sets lap record to take pole at Italian GP
29/05/2021 AT 18:04