It's hard to tell if this is a message sending to Petterson/the league that he might be available, or he's not really available, but if a team were to go bananas and offer something you couldn't say no to available.
Right now I'd say the Nucks are dealing an 80 point centre, however he's on track again for his 4th season of high 60s for points.
If he's tracking that way next year, then teams will likely view him as a below 80 point centee and at that contract I can't imagine the Nucks would get much back.
So, in short this offseason is likely where they need to decide if he's apart of the future, or traded for a piece/pieces that hopefully will be apart of the future.