Rubuta ci gaba don wannan sakin layi - Walman ya buga wasan hockey na matasa tare da Toronto Jr. Canadiens a cikin Ontario Junior Hockey League (OJHL) kafin ya yi wa kwalejin kwalejin kwaleji tare da Providence College na Hockey East. Kafin lokacinsa na farko tare da Friars, an zaɓi Walman a cikin NHL Entry Draft na 2014
a zagaye na uku, na 82 a duka, ta St. Louis Blues.