Management really bungled this season. The Pettersson deal is kind of emblematic of it to me.
Why did they wait until game 50 or whatever to make it? Everyone knew they needed to add another top-four defenseman. PIT has been signalling they're in sell mode the entire year. Marcus Pettersson is a JR guy. It was inevitable he was going to land in Vancouver. What took so long? They could have flipped their own 1st for him at any time (and I would have much preferred they traded their own 1st in this deal than the Rangers' - I will laugh when they've gifted McKenna to the Pens).
If they acquire Pettersson earlier, maybe the team has a better record and the bad vibes from Petey/Miller are mitigated, so they aren't forced into a trade either.
This season is on management.