2010-11: Ben Thomas skated for the Calgary Northstar Sabres bantam AAA team and played for the Calgary North Stars in the 2011 Alberta Cup. He scored 1 goal with 3 assists and had 2 penalty minutes in five games at the Alberta Cup. Thomas was selected by the Calgary Hitmen in the third round (45th overall) in the 2011 WHL Bantam Draft.
2011-12: Thomas made the jump from bantam hockey to midget majors — skating in the Alberta Midget Hockey League with the Calgary Northstars. In 34 regular season games he scored 2 goals with 15 assists and had 46 penalty minutes. The Northstars finished third in the Chrysler Division. Thomas did not appear in any playoff games.
2012-13: Thomas skated in three pre-season games with the Hitmen before playing junior A hockey in Calgary and made his WHL debut with Calgary in the playoffs. He had no points nor penalty minutes in his only game with the Hitmen. Thomas began the season with the AJHL’s Calgary Mustangs — skating in 12 games and scoring 1 goal with 4 penalty minutes — before a mid-season trade to the Calgary Canucks. In 32 games with the Canucks he scored 4 goals with 3 assists and had 33 penalty minutes. The Canucks finished last in the South Division.
2013-14: Thomas spent his first WHL season with the Calgary Hitmen and played for the Canada U18 team in the 2014 World Junior Championship. The lone player to skate in all 72 regular season games for the Hitmen, he scored 7 goals with 24 assists and was +11 with 39 penalty minutes. Calgary finished first in the Central Division, falling to fourth-place Kootenay in a first-round playoff series. Thomas scored 1 goal with 5 assists and was +5 with 13 penalty minutes in six playoff games. Thomas had 1 assist and was +2 with 2 penalty minutes in seven games for Canada at the U18 WJC. Canada defeated Sweden 3-1 in the bronze medal game. Thomas was selected to play for Team Orr in the 2014 CHL/NHL Top Prospects Game. He was ranked 86th in the Central Scouting final rankings and was selected by Tampa Bay in the fourth round (119th overall) in the 2014 NHL Draft.
2014-15: Thomas skated in 60 regular season games for the Calgary Hitmen in his second WHL season — missing most of December due to injury. He scored 7 goals with 24 assists and was +14 with 28 penalty minutes. The Hitmen finished first in the Central Division and reached the Eastern Conference finals against Brandon. Thomas had 4 assists and was -5 with 2 penalty minutes in 17 playoff games.
Thomas is a big, sturdy defense-first defenseman who has shown flashes of an offensive game. He has been challenged against speedy and highly-skilled forwards at times but should continue to develop as he matures physically and gains experience. He is fairly mobile for a large player though he is not an overly punishing player given that size.
Thomas matched his offensive totals from his first junior season despite missing 12 games in 2014-15 in his second season with the WHL's Hitmen. Overshadowed at times by teammates Travis Sanheim (Philadelphia) and impressive 16-year-old Jake Bean on the Calgary blue line, Thomas is a steady, reliable presence on the back end. He projects as a sound, second or third pairing defenseman at the NHL level. He is still fairly early in the development process.