Rule 6.2 of the 2008 â `` 09 Official NHL Rulebook says that '' ( only ) when the Captain is not in uniform , the Coach shall have the right to designate three Alternate Captains . Rule 6.2 of the 2008 â `` 09 Official NHL Rulebook indicates that '' ( only ) when the Captain is not in uniform , the Coach shall have the right to designate three Alternate Captains .