... After all, for the new Tron movie they needed a young version of a character, so they did almost exactly this - recreated him entirely in CGI. But it's Disney! So no moral problems there!
Actually, that's because the actor in question is actually acting in the movie. Also, is it a fully CGI version, or is it just digital de-aging, like they did for Magnus and Xavier in X-Men III? The former would make it more like Golem being modeled on Andy Serkis; latter would simply make it Jeff Bridges playing two roles in the same film.
Wikipedia to the rescue; looks like the former.