The France forward has been seeking a move away from Loftus Road all summer and was close to joining Liverpool in July, only for the deal to collapse after he flew to the USA for a medical.
Remy, understood only to desire a move to a Champions League club, turned down the chance to re-join Newcastle on a permanent deal last week, after spending last season at St James’ Park on loan.
The 27-year-old has featured in both Rangers two Premier League games so far this season, and manager Harry Redknapp has been keen for him to stay, but Remy is set to move across west London and compete with Diego Costa and Didier Drogba.
Should the deal go through, Remy will replace Spain striker Fernando Torres, who is to undergo a medical at AC Milan on Saturday after agreeing terms on a two-year deal.
Remy was omitted from the Rangers squad for Saturday's Premier League game against Sunderland at Loftus Road ahead of his imminent move to Chelsea.
Redknapp told Sky Sports: "I just got a phone call at about 12 o’clock today - he was going to play today - to say that it looks like he is going to be moving.
"I spoke to the boy - it’s difficult isn’t it? - he’s gut to move and the deal looks like it is probably done so I had to make a change in the team.
"He didn't refuse to play or anything, but speaking to him it is difficult. If he is moving tonight and signing for another team, it’s difficult to go out there and get your head around playing today.
"So I just felt it was better we go with someone who is here, and going to be part of what we are doing, and one who has got nothing else going on in his head apart from trying to get a result for us."
Rangers, meanwhile, are set to sign former Real Madrid midfielder Lassana Diarra, who will also undergo a medical in west London on Saturday.