Of course, he was 45th in plus minus, at plus one.
http://www.nhl.com/stats/player?reportType=season&seasonFrom=20172018&seasonTo=20172018&gameType=3&position=D&filter=gamesPlayed,gte,1&sort=plusMinus
But I hear that's "stupid."
He was 65th in hits per game played, which is almost playoff top four territory.
He was 39th in shots blocked per game played, which is his best claim to be a #3 defenseman in these playoffs.
You could argue that those are meaningful stats. But then you'd be stuck looking at who else did well in them, and calling them good defensemen.
Orpik was 1st, 7th, and 23rd in those stats, making him a #1, #1, and #2 defensive defenseman in the playoffs and got bought out. It is reasonable to assume Kempny will be about as good next year as Orpik, if Orpik keeps aging, but the year after that, I'd rather have Schenn, Siegenthaler, Johansen, or Lewington than either of them, so giving Kempny a long term deal and paying him like a weak #4 defenseman is, at best, really optimistic and sentimental. At worst, it's passing on a chance to sign Kevin Connauton, who scored 11 goals last year in Arizona (21st among defensemen on 31 teams, so #1 territory, but his only claim to be a top pairing guy that I've noticed, meaning he might sign around 3M a year, and keep developing that offense). At worst it's keeping the Caps from signing Burakovsky next summer.
At best he's the next Calle Johanson--decent skater who's okay defensively, can make quick passes, and will get a lot of assists as long as he's paired with one of the best goal scoring defensemen in the game. But Carlson's 15 goals this past season were his career high, and he played more of the year with Orpik than Kempny. I really would have been fine to just ride out the last year of Orpik's contract and then bring up Lucas Johansen for that spot.
Is my post above a slight hyperbole? Yes. Would I trade Kempny for a bag of popcorn? No. But would I have greatly preferred to see him offered 2Mx3years so he had much more positive trade value next summer? Yes. That is the point that I am making.