Chelsea have a recall clause in McEachran's loan deal at the Riverside, which runs until May.
McEachran, 19, who can help Boro to the top of the Championship table with a big win at Birmingham tonight, said: "I've been at Chelsea since the age of seven and I've grown up there.
"It's always been my dream to play regular first-team football there.
"But I'd like to stay here for the season. We have a genuine chance of going up and I want to be part of it.
"There's a long way to go and a lot could happen but we have a really good manager and I like the way he wants to play."