The 2-2 draw with Dortmund brought further frustration for Bayern, who saw Saibari, Gnabry and Michael Olise all forced off with injuries. The situation has left the club assessing its options ahead of Tuesday's Champions League meeting with Atletico Madrid.
Saibari suffered the most serious injury, sustaining a tear to the syndesmosis ligament in his right ankle after a challenge involving Dortmund goalkeeper Gregor Kobel. The Morocco international has already undergone successful surgery.
Reports in Germany suggest he could be sidelined for at least three months, representing a significant absence for Bayern.
Gnabry also sustained a muscle injury, affecting the back of his left thigh. His expected recovery period has been reported as four to six weeks, although Bayern have not officially confirmed a return date.
Olise was the third attacking player to leave the Dortmund match with a problem, suffering knee pain. The club has yet to provide a diagnosis, leaving his availability for the Atletico fixture uncertain.
Bayern are also without Luis Díaz, who suffered a minor muscle tear in his left hamstring around a week and a half earlier. His recovery has been estimated at four to six weeks.
Jamal Musiala has been absent since the end of September after sustaining a muscle tear in his right thigh while away with the Germany national team. Bayern's internal target is reportedly for him to return before the international break in mid-November, with Saturday's meeting against Mainz identified as a possible date.
There are further concerns in goal. Jonas Urbig collided with Dortmund's Carney Chukwuemeka and is being assessed for possible concussion symptoms or other complications. His availability for Atletico remains uncertain.
Manuel Neuer is also a doubt. The captain has been struggling with persistent pain and swelling associated with tendinitis, and a return in time for the trip to Madrid is considered difficult.
Should both goalkeepers be unavailable, Sven Ulreich would be in line to step in.
Midfield youngster Bara Sapoko Ndiaye is another absentee after undergoing surgery for appendicitis.
The growing list of injuries is particularly concerning given the timing of Bayern's upcoming fixtures. Vincent Kompany is also recovering from a health issue described in the supplied report as a brain irritation, adding to the challenges facing the coaching staff.
Bayern Munich will need to assess their remaining options carefully before travelling to Spain, with several key players facing a race against time to return.