Karlsson averages 67 points per 82 games in his career.
It's fair to say he was below his average for us offensively, since he got 56. Maybe that goes up by 5 points or so next year, but temper your expectations there. Maybe better on the PP but worse at ES.
On the flip side, we got an above average defensive season out of him, based on his career standard. It still wasn't even that good compared to other 1D's in the league. It's realistic to expect a drop-off there next year as well, since he won't be eager to impress this time out of the gate. It's likely he gets sloppier and lazier earlier in the season next time.
So where would that leave his value? I don't see a 10 mil D-man there at all. That's a 7 mil D-man.
He's not Adam Fox.
Plus the Pens are really sacrificing 11.5M to have EK play here, because they ate the Petry retention en route. That makes it even worse.
They were better off not making this trade, and just letting the bad short-term contracts expire.