They've done it before; can't see why they wouldn't do it again now (see the TV-show, where Nordberg was played by some other guy).
I think the first Naked Gun movie is among the best of comedy available on film (IMO), so I'll be keeping an eye on this.
Actually, OJ was the recast Nordberg. The TV show predated the films.
The Naked Gun is a series of three comedy films from 1988 to 1994, written and produced by the comedy filmmaking trio Zucker, Abrahams and Zucker and distributed by Paramount Pictures. It was based on their short-lived 1982 ABC television series Police Squad!, which was cancelled after six episodes.
This sounds interesting but if its straight to DVD it will be forgotten quickly, even if it is good.
Edit: A funny note about the TV show is that each episode started off with a "special guest star" being killed in the opening scene. John Belushi filmed a segment but died before the episode aired, leading to a decision to not use his sequence, which has since been lost.