A few things to keep in mind:
While there is a roster freeze starting today, that doesn't prevent teams from recalling players from the AHL. The roster freeze is to protect players from being traded or demoted just before Christmas. It's not to prevent players from getting the chance to play in the NHL.
Wotherspoon's last recall was on December 8. Any players recalled after December 11 can still be sent down during the roster freeze (up until midnight on December 23rd). This gives the Flames the option of demoting him after the game on Friday and then recalling him (or Kulak) prior to Tuesday's game next week. That would save them three days of NHL salary and cap hit, plus gain another three days of waiver exemption.
This morning, CapFriendly tweeted this guide to the roster freeze:
Also, of note is that Kulak played in Stockton's game on Friday and Wotherspoon was seen leaving the Saddledome prior to Friday's game with his gear, so Wotherspoon's demotion was likely not a response to Kulak's injury. It's likely that the plan was to recall Kulak again but his injury led to Wotherspoon's recall instead.
