Remy, 27, was originally named in QPR's team to face Sunderland but Redknapp withdrew him after being told the club had accepted a bid for the French striker.
"He was in the team. I just got a phone call ... to say it looks like he is going to be moving," Redknapp said.
"The deal looks like it has been done, so I had to make a change. He didn't refuse to play but it's difficult to go out there to play and get your head around it.
"As far as I know (it is Chelsea)."
With Fernando Torres expected to join AC Milan on a two-year loan deal, Chelsea manager Jose Mourinho would like another striker to compete with Diego Costa and Didier Drogba.
Remy scored 14 goals in 26 league games while on loan at Newcastle United last season and seemed to be heading to Liverpool earlier in the transfer window but failed a medical.