Standard Sport understands that Dujon has agreed to join Rangers on a free transfer at the end of the season, having grown frustrated at a lack of opportunities at Stamford Bridge.
Sterling has spent 15 years with Chelsea, joining the academy as an eight-year-old, but has been afforded just one senior appearance. The defender has regularly been sent out on loan and is currently impressing at Stoke.
Beale coached Sterling while in charge of the Blues academy so the impending move is a reunion for the pair.
Asked about Sterling's expected arrival, Beale was reluctant to talk on the subject.
"There is a lot of speculation and names but until anything is concrete we don't want to talk about any individual players," he told reporters.
"He is a good player but I don't want to say any more than that."