The Gunners take on the Blues at Emirates Stadium on the back of a worrying run of form, having lost three of their last six league matches.
Their latest defeat, a 1-0 reverse to West Ham last weekend, left Arsenal 16 points back of first-place Liverpool and six points behind fourth-place Chelsea.
Defeat to the Blues on Saturday, then, would leave Arsenal nine points back of the top four, a mountain Emery admits would be almost impossible to climb.
When asked if a nine-point gap would be too much to overcome for his side, Emery replied: “I think yes."
A positive result against Chelsea will be paramount for the Gunners, and Emery is aware where his opponents' greatest threat will lie.
“With a player like (Eden) Hazard, usually all of the big teams in the world will think about the possibility of trying to sign them,” Emery said.
“He is in the top five players in the world. He has been the difference in a lot of matches.”
Arsenal's formation on Saturday is yet to be determined, with Emery's side having rotated between three-man and four-man defences.
Emery explained that he has been switching his formation up this season depending on game situations.
“I think the best possibility for us when we can’t control the match like we want is to sometimes use three centre-backs,” Emery said.
“But at other moments, we need to play with full-backs because we need to control a different situation, with more players in the midfield.”
Arsenal and Chelsea will be the late kick-off on Saturday, with the match set for 17:30 GMT.