In my opinion of the 10 goals against, one was Coburn's fault, two were inconclusive, and seven were not his fault. Over those same 10 goals against, Grossmann was out there with Coburn on six of them, and was at fault for just as many. This is less an indictment of Grossmann and more of a plea to not pin the failings of the penalty kill on any one individual. Especially the guy that has played the most minutes in recent years on one of the league's top penalty kills.
We've seen it enough times now to know that Coburn functions far better as the #2 on a given pairing. We've seen him excel with Timonen and be pedestrian when asked to do more. It's not as if Coburn is without fault with respect to the sideshow the Flyers call a defense corps right now.
However, choosing an arbitrary line in the sand by which to judge goals against numbers isn't reflective of Coburn's play. He shouldn't be scratched for it. He is not to blame for the bad penalty kill. It's just ... a pretty bad penalty kill that really misses a couple of key contributors.