So that's a pretty clear ankle sprain. But given that he was able to walk out on his own I'd guess that at worst its a grade 2 ankle sprain which is a four week recovery. The playoffs start in four weeks. So even in the absolute worst case scenario he'd be back in time for the start of the playoffs. More likely I think its a grade one sprain and he's out 1-2 weeks, which is fine becasue I expect they'd be retsing him some the next few weeks anyway.
In short, not really worried about what it means for the C's playoff run. If this happened in round one it would be a bigger deal, but right now plenty of lead up time still left.