My guess is a straight-up replacement with CB Justin Green, since safeties Harmon, Wilson, and Ebner are not on the injury report, and the only CB not listed is Logan Ryan, and Dennard is on there twice. Consider also that Alfonso Dennard played 5 snaps against the Ravens while Logan Ryan drew 71 snaps. We all like Ryan but I don't think that happens if Dennard isn't on the injury report with both leg and shoulder injuries.
Given that Green is currently being paid well over practice squad minimum, the Pats seem to have put a premium on his raw talent. And unlike Kanorris Davis, who has so-far been a pure ST fill-in, in Green's one previous game (vs. Broncos) he actually logged about a dozen defensive snaps, so I think the Pats cut Cole because they want to (a) rest Dennard for the playoffs and (b) see if Justin Green can play better defense than Cole.
I think Justin Green is about to get a tryout for the playoff roster.