PK time does not count for +/- ratings, it's for even strength play. He's been a liability defensively throughout his career.
Now you're re-writing history. Sal had a very long run of being a stable defensive defenseman before slowing down the last few years. He was a major cog when he came over in the Janssen trade, and through his next contract. The last couple of years he's slowed down considerably, but to suddenly say he wasn't good defensively throughout his career is just wrong.