Bowman was selected eighth overall by the Spokane Chiefs in the 2004 WHL Bantam Draft.
He debuted in four games with the Chiefs in 2004–05, a season he spent primarily at the Junior B level with the Kimberley Dynamiters of the Kootenay International Junior Hockey League (KIJHL).
He recorded 29 goals and 59 points over 47 games with the Dynamiters to be named the Eddie Mountain Division's rookie of the year.
Bowman joined the Chiefs full-time in 2005–06 and notched 17 goals and 34 points over 72 games (17th in WHL rookie scoring) to be named the team's rookie of the year.
On a team basis, the Chiefs finished last in the Western Conference and failed to qualify for the playoffs.

Bowman entered the 2006–07 season listed as the ninth-best WHL prospect in the NHL Central Scouting Bureau (CSB)'s preliminary rankings of draft-eligible players.
He was invited to play in the CHL Top Prospects Game and was subsequently listed in the CSB's midterm rankings as 44th among North American skaters.
Bowman finished the season with an improved 24 goals and 43 points in 61 games.
He played in his first WHL playoffs after the Chiefs ranked fourth in the U.S. Division.
Playing in six post-season games, Bowman recorded a team-leading seven points (two goals and five assists).
The Chiefs were eliminated in the first round by the Everett Silvertips.
Entering the 2007 NHL Entry Draft in the off-season, he moved up to 36th among North American skaters in the NHL CSB's final rankings.
Bowman was selected 72nd overall by the Carolina Hurricanes.

Following his draft, Bowman participated in his first NHL training camp in September 2007 before being returned to Spokane to continue playing at the junior level.
Playing in his third full WHL season, Bowman recorded a team-leading 82 points in 66 games.
His 42 goals tied for fourth in the league.
Bowman added a team-leading 20 points in 21 playoff games as the Chiefs captured the Ed Chynoweth Cup as WHL champions.
The league title earned the Chiefs a berth in the 2008 Memorial Cup in Kitchener, Ontario.
Bowman notched a hat trick in the opening game of the tournament, including the game-tying goal late in the third period of a 5–4 overtime win over the Belleville Bulls.
He went on to score in all four games of the tournament, including game-winners against the Kitchener Rangers in the round-robin and final.
The Chiefs went undefeated in the tournament to capture the Memorial Cup as Canadian major junior champions, beating the Kitchener Rangers 4–1 in the final.
With a team-high eight points (third in tournament scoring behind Justin Azevedo and Matt Halischuk of the Rangers), including a tournament-leading six goals, in four games, Bowman was named to the Memorial Cup All-Star Team.

Following his Memorial Cup performance, the Hurricanes signed him to a three-year, US$2.06 million contract on July 31, 2008.
Playing in his final season with the Chiefs in 2008–09, Drayson was named an alternate captain to Justin McCrae along with Seth Compton and Jared Spurgeon.
He was named WHL and CHL Player of the Week after recording 12 points in 3 games for the week ending on February 1, 2009.
The next month, he earned his second WHL and CHL Player of the Week distinctions with an eight-point effort in two games for the week ending on March 15, 2009.
He finished the season with 47 goals, fourth in the league, and a junior career-high 83 points to lead his team in scoring for the second consecutive year.
He was named to the WHL West Second All-Star Team along with goaltending teammate Dustin Tokarski.
Bowman and the Chiefs were not able to defend their WHL or CHL titles as they were eliminated in seven games in the second round of the WHL playoffs by the Vancouver Giants.
Spokane's elimination marked the end of Bowman's junior career.
He left the Chiefs fifth on the team's all-time goals scored list with 136, 10 behind leader Pat Falloon.
He had 114 assists for 250 points total over 269 games.
Bowman was selected eighth overall by the Spokane Chiefs in the 2004 WHL Bantam Draft. He debuted in four games with the Chiefs in 2004–05, a season he spent primarily at the Junior B level with the Kimberley Dynamiters of the Kootenay International Junior Hockey League (KIJHL). He recorded 29 goals and 59 points over 47 games with the Dynamiters to be named the Eddie Mountain Division's rookie of the year. Bowman joined the Chiefs full-time in 2005–06 and notched 17 goals and 34 points over 72 games (17th in WHL rookie scoring) to be named the team's rookie of the year. On a team basis, the Chiefs finished last in the Western Conference and failed to qualify for the playoffs.
Bowman entered the 2006–07 season listed as the ninth-best WHL prospect in the NHL Central Scouting Bureau (CSB)'s preliminary rankings of draft-eligible players. He was invited to play in the CHL Top Prospects Game and was subsequently listed in the CSB's midterm rankings as 44th among North American skaters. Bowman finished the season with an improved 24 goals and 43 points in 61 games. He played in his first WHL playoffs after the Chiefs ranked fourth in the U.S. Division. Playing in six post-season games, Bowman recorded a team-leading seven points (two goals and five assists). The Chiefs were eliminated in the first round by the Everett Silvertips. Entering the 2007 NHL Entry Draft in the off-season, he moved up to 36th among North American skaters in the NHL CSB's final rankings. Bowman was selected 72nd overall by the Carolina Hurricanes.
Following his draft, Bowman participated in his first NHL training camp in September 2007 before being returned to Spokane to continue playing at the junior level. Playing in his third full WHL season, Bowman recorded a team-leading 82 points in 66 games. His 42 goals tied for fourth in the league. Bowman added a team-leading 20 points in 21 playoff games as the Chiefs captured the Ed Chynoweth Cup as WHL champions. The league title earned the Chiefs a berth in the 2008 Memorial Cup in Kitchener, Ontario. Bowman notched a hat trick in the opening game of the tournament, including the game-tying goal late in the third period of a 5–4 overtime win over the Belleville Bulls. He went on to score in all four games of the tournament, including game-winners against the Kitchener Rangers in the round-robin and final. The Chiefs went undefeated in the tournament to capture the Memorial Cup as Canadian major junior champions, beating the Kitchener Rangers 4–1 in the final. With a team-high eight points (third in tournament scoring behind Justin Azevedo and Matt Halischuk of the Rangers), including a tournament-leading six goals, in four games, Bowman was named to the Memorial Cup All-Star Team.
Following his Memorial Cup performance, the Hurricanes signed him to a three-year, US$2.06 million contract on July 31, 2008. Playing in his final season with the Chiefs in 2008–09, Drayson was named an alternate captain to Justin McCrae along with Seth Compton and Jared Spurgeon. He was named WHL and CHL Player of the Week after recording 12 points in 3 games for the week ending on February 1, 2009. The next month, he earned his second WHL and CHL Player of the Week distinctions with an eight-point effort in two games for the week ending on March 15, 2009. He finished the season with 47 goals, fourth in the league, and a junior career-high 83 points to lead his team in scoring for the second consecutive year. He was named to the WHL West Second All-Star Team along with goaltending teammate Dustin Tokarski. Bowman and the Chiefs were not able to defend their WHL or CHL titles as they were eliminated in seven games in the second round of the WHL playoffs by the Vancouver Giants. Spokane's elimination marked the end of Bowman's junior career. He left the Chiefs fifth on the team's all-time goals scored list with 136, 10 behind leader Pat Falloon. He had 114 assists for 250 points total over 269 games.
Drayson Bowman