If I'm not mistaken (thanks once again Foligno!) Greene was switched back to the other side after Salvador was injured. It took the Salvador injury just for that tool to put Greene back where he should have been all along.
At the same time though, Salvador was not good when he was in the lineup last season. In fact, he's been pretty brutal for the last 2 or 3 seasons. I'd say ever since the last lockout ended. Or at least by the 13-14 season he was pretty awful. He was fairly serviceable in 12-13, though not good. He was also being played way too many minutes, more than any season in his career aside from the 11-12 season. More than any season in his prime at least. Not sure if that was a Stevens or DeBoer thing, but he was being way overused.
I remember Salvador doing a lot of horrendous things the last we saw him, though I don't blame him for the PK gaffes as much as Greene playing on the wrong side. It's like the same thing was happening EVERY time we allowed a PK goal for the first 5 or 6 weeks of the season. Greene would get caught because he wasn't used to playing that side. I'm sure Salvador caused a couple of those PK goals though, he also did quite a few mind numbingly horrific things at even strength. He was even benched for the duration of a game after one of the worst turnovers we might have seen all season, I think Cory made the save and Salvador was benched for the rest of the game, by Pete DeBoer of all coaches. It was in the first half of the 3rd period and we didn't see him for the rest of the game, or he might have played a shift.
I think it might have been that game we won our first shootout (in a couple years) against Winnipeg last season. I think Pete claimed that he was benched because we needed a goal because we were tied or down in the game.