I doubt it's in Chelsea's mind currently to let Lakaku go but the thing with them lot and all there cash "you just never know". As was seen with Rooney this summer if they see a top striker possibly available they will go for him. They could quite possibly bring in and spend multi millions on 2 strikers next summer (Ibra) for eg. or whoever else becomes available.
From there alot depends on Lakaku, is he happy being 3rd choice at Chelsea and desperate to prove his worth there, or does he fall in love with our club and rather a move to be star man?
Who knows! But don't count anything out.