Argentina international Pastore has been ruled out of the Ligue 1 champions' visit to the Stade Jacques Chaban-Delmas with a foot injury, while forward Menez - who has yet to play in 2013-14 - is still absent after undergoing back surgery in the close-season.
"Jeremy Menez and Javier Pastore are not available for the Bordeaux trip," Blanc said on Thursday.
However, Brazilian defender Marquinhos - who joined from Roma for a fee of €31.4million in the close-season - could be set to make his first appearance for the club after recovering from a virus.
"Marquinhos is now healed. He is within the group, but I'm not sure (he can play) 90 minutes," the manager added.
Blanc managed Bordeaux to a Ligue 1 and Coupe de la Ligue double in 2009 as part of a successful three-year stint in charge at the club, and is looking forward to returning with PSG.
"It is with pleasure that I return to Bordeaux, a personal and professional point of view," the 47-year-old stated.
PSG have made a stuttering start to their title defence, taking eight points from their opening four games despite strengthening their squad with the likes of Marquinhos and Edinson Cavani before the start of the new campaign.
However, they have won their last two matches, and Blanc insisted they will look to take maximum points again at Bordeaux.
"Bordeaux has offensive skills but we do not know if they take risks. We are going to impose (themselves)," he added.
