Saibari was forced to withdraw from the Klassiker against Borussia Dortmund in the 29th minute after colliding with goalkeeper Gregor Kobel, two minutes before Gnabry was also forced to leave the contest.
The day after the 2-2 draw, the club confirmed that Saibari had torn the syndesmosis ligament in his right ankle and had already undergone successful surgery, while Gnabry sustained a muscle injury in the posterior left thigh.
Technical director Max Eberl confirmed on Monday the timetables for the midfielders' returns, with Saibari out for months.
"He was already sitting with us at lunch today. I was completely surprised and asked him whether it would be two or three weeks. He laughed a little and said: ‘Two and a half.’ That probably won’t be the case. We’re expecting him to be out for three to four months with the syndesmosis ligament tear," Eberl said during the press conference ahead of the club's UEFA Champions League clash against Atletico Madrid.
Gnabry will be out for a shorter time, with the Germany international expected to be sidelined until Christmas.
Bayern Munich face Atletico Madrid on Tuesday, November 3rd, at 21.00 CEST.