Which players could sign an eight-year extension before CBA change?

NHL teams can no longer re-sign players to contract extensions longer than seven years starting September 16. Columbus Blue Jackets forward Denton Mateychuk is identified as a player who could sign an eight-year deal before the new collective bargaining agreement takes effect. The article notes Mateychuk had 13 goals and 31 points last season while on his entry-level contract.