The impending decision by free agent Mats Sundin on where he will continue his NHL career may be complicated slightly by the NHL's Holiday Roster Freeze, a nine-day restriction on most roster moves.Sundin, an unsigned Group 3 free agent, is expected to make his decision Thursday, reportedly weighing final offers from the Vancouver Canucks and New York Rangers If Sundin chooses the Rangers, for example, the club will likely have to make several moves to free up salary-cap space and pare down its roster, which currently stands at 23. Vancouver might also have to make at least a roster move to bring Sundin into the fold. Whatever moves proved to be necessary for either club would have to be made before Sundin could officially sign a contract.So, the signing team would have to make the necessary roster alterations before midnight (local time) Friday in order to beat the start of the Holiday Roster Freeze. If not, the club would have to wait until after midnight (local time) on Dec. 27, the expiration of the moratorium, to make the necessary moves.What exactly is the Holiday Roster Freeze?It is a proviso of the current Collective Bargaining Agreement that limits the movement of players around the Christmas holiday.Simply stated, it prevents any players on NHL active rosters or injured reserve from being traded, waived or loaned from midnight (local time) Dec. 19 until midnight (local time) on Dec. 27.There are a couple of exceptions to this rule. Teams may sign players during the roster freeze or call up players if roster space becomes available. Also, if a player is placed on waivers before Dec. 19, he must immediately report to any team that claims him during the Holiday Roster Freeze period.NHL clubs also can make any roster moves necessary to come into salary-cap and roster limits when removing a player from the Bona Fide Long-Term Injury/Illness Exception.