Celtic needed a late comeback from 2-0 down at Hibernian to clinch a 2-2 draw, with Edouard scoring from the penalty spot after he was brought on off the bench.
Despite the comeback, Celtic still dropped two points at Easter Road and are now eight points behind Rangers, albeit with a game in hand.
Eyebrows were raised at Edouard being left on the bench when the team was named and Rae believes it is essential that the Frenchman is restored to the team by Lennon.
Rae said on Radio Clyde’s Superscoreboard: “The big question mark for me is why Edouard did not start.
“He absolutely terrorised the two centre halves and he’s such an integral part to this team.
“Whatever is going on behind the scenes it needs to be put to bed before it’s too late.”
Rangers can move eleven points clear if Celtic if they put Aberdeen to the sword at Ibrox on Sunday.
Celtic are next in action in the Europa League away at Sparta Prague, while their next league clash comes at home against Ross County.