If Boston is lucky he doesn't re-sign. Would be such a mistake for them

I would definitely pass on Krug at $7M+. In my opinion PP specialists are usually overpaid. So are 30 y.o. UFA's. Krug would need to take a hometown discount for the cap numbers to work and his offensive stats are definitely inflated playing on an elite PP unit. He's also been a little injury prone in recent seasons.

krug at 6 or less would be fine. otherwise let him walk. not worth the $$

Why would he want to go to Detroit?

Source?

Did you check out his bio? Born: Royal Oak, Michigan. Raised in Livonia, Michigan. 3 brothers live in the area. His wife's family lives in the area. He's a Michigan State grad that complete his last 38 credits online taking classes during his first 5 NHL seasons.
Before the bubble:
He was coached by Red Wings head coach Jeff Blashill who was a coach with the Indiana Ice of the USHL at the time.

He's a power play QB that would be a position of need for the Wings whose PP ranked 29th in the league this season. In the last 2 years the Wings have lost Niklas Kronwall, Trevor Daley and Mike Green as veteran leaders. Danny DeKeyser joined the team in 2013 so even he doesn't have Stanley Cup experience that can be passed down to the young prospects (like Seider, Cholowski, McIsaac, and Lindstrom)--but Krug does. And Seider would be a perfect pairing on the 2nd pair as Krug is more offensively adapt balanced by Seider's defensive strengths.
Wings have empty roster spots for LHD and 36M and change in cap space.
....but he's also got strong Boston ties including naming his dog: Fenway. So it's possible he stays with the Bruins on a team-friendly cap hit.

I could see it.