2009-10: Dakota Mermis appeared in two USHL games with the Lincoln Stars and played for the St. Louis Blues U18 team in the Midwest Elite Hockey League. He had one assist in his brief stint with the Stars. In 48 games for the Blues he scored 11 goals with 26 assists and had 76 penalty minutes. Mermis committed to playing college hockey at the University of Denver in 2012-13.
2010-11: Mermis moved to the USA National Team Development Program in Ann Arbor; skating for the NDTP U17 team. In 55 games he scored 5 goals with 8 assists and had 63 penalty minutes. Mermis played for the USA in the 2011 U17 World Hockey Challenge and had 1 assist with 4 penalty minutes in six games. The USA won a silver medal, falling to Team Ontario in the championship game. Mermis was drafted by Green Bay in the first round (14th overall) of the 2011 USHL Entry Draft.
2011-12: Mermis was one of four defensemen to top the 25-point mark on a dominant Gamblers team that won a USHL-best 47 games. Mermis scored 5 goals with 22 assists and was plus-22 in 60 games. His 98 penalty minutes were the second-most for Green Bay behind only Sheldon Dries (126). Heading into the decisive fifth game against the Waterloo Black Hawks in the USHL playoff finals, Mermis had 1 assist and was plus-three with 11 penalty minutes in 11 playoff games. Mermis was ranked 84th amongst North American skaters in Central Scouting’s final rankings prior to the 2012 NHL Draft.
2012-13: Mermis skated in 19 games for the University of Denver as a freshman before leaving college hockey in January to play for the OHL’s London Knights. He scored 1 goal with 3 assists and was minus-one with 14 penalty minutes for the Pioneeers. Mermis had two assists in his first game with the Knights and finished the regular season with 2 goals and 9 assists in 26 games and was plus-17 with 30 penalty minutes. London had the OHL’s best record and won the playoff title after trailing Barrie three games to one in the finals. Mermis had no 1 points and was +1 with 10 penalty minutes in the four games at the Memorial Cup.
2013-14: Mermis skated for the Columbus Blue Jackets’ entry in the annual Traverse City rookie tournament but was not signed, returning to London for his first full OHL season. In 66 regular season games he scored 5 goals with 20 assists and was +40 with 76 penalty minutes. London finished third in the Midwest Division, advancing to the second round in the OHL playoffs, and participated in the Memorial Cup as the host team. Mermis scored 1 goal with 3 assists and was +10 with 12 penalty minutes in nine OHL playoff games and was -3 with 1 goal and 2 penalty minutes in three games at the Memorial Cup.
2014-15: Mermis attended rookie camp with Arizona before returning to London for an overage season in the OHL. Acquired by Oshawa along with Montreal Canadiens’ prospect Michael McCarron as part of a trade deadline deal in January 2015, he was part of the Generals’ Memorial Cup-winning team. In 36 games prior to the trade he scored 1 goal with 10 assists and was +22 with 36 penalty minutes. Mermis scored 5 goals with 14 assists and was +26 with 50 penalty minutes in 30 regular season games for Oshawa. The Generals had the league’s second-best regular season record in winning the East Division. Oshawa captured the OHL championship, defeating Erie in the playoff finals, and topped WHL champion Kelowna, 2-1 in overtime, in the Memorial Cup championship game. Mermis scored 1 goal with 14 assists and was +12 with 14 penalty minutes in 21 OHL playoff games and was +5 with 1 goal, 2 assists and 4 penalty minutes in four Memorial Cup games. Arizona signed Mermis to a three-year entry-level contract as an undrafted free agent in July 2015.
Mermis joined the OHL’s London Knights half-way through the 2012-13 season after leaving the University of Denver en route to that year’s NHL Draft. Steady in all areas, but unspectacular, he played a solid defensive game and steadily improved his offensive play in his two-plus seasons in the OHL. He was a steady force on the blue-line and rarely was noticed for any defensive gaffes with London before being acquired by Oshawa and being a strong force during the Generals' successful run to the 2015 Memorial Cup championship.
Mermis was signed by Arizona as an undrafted free agent in July 2015 following an overage season in the OHL, starting the year with London before being acquired by London at the trade deadline and skating with the Generals during their Memorial Cup championship campaign. He will likely begin his pro career with new Coyotes' AHL affiliate Springfield in the fall.