2007-08: Duncan Siemens was chosen in the first round, 3rd overall, of the 2008 WHL Bantam Draft by the Saskatoon Blades.
2008-09: Siemens played for the Sherwood Park Kings Midget AAA team, appearing in 34 games for that team. He scored 5 goals and added 13 assists for 18 points, while also chipping in with 68 penalty minutes. Siemens made his WHL debut with the Saskatoon Blades, playing in 2 games and recording 1 assist.
2009-10: Siemens played in his WHL rookie season with the Blades appearing in 57 games for that team. He scored 3 goals and added 17 assists for 20 points along with 8 penalty minutes. In 7 playoff games for the Blades, Siemens had no points and 11 penalty minutes. Siemens played for Team Pacific at the 2010 World Under-17 Hockey Challenge, picking up no points and 10 penalty minutes.
2010-11: In 72 games for the Blades, Siemens scored 5 goals and added 38 assists for 43 points. He also added 121 penalty minutes on the season. Siemens played for Team Cherry at the 2011 CHL Home Hardware Top Prospects Game.
2011-12: Siemens made his pro debut as an 18-year-old – playing in three late season games with Colorado’s AHL affiliate Lake Erie following his third season with Saskatoon. He was scoreless and minus-one with 2 penalty minutes during his time with the Monsters. Playing on the top pairing for Saskatoon along with Montreal prospect Dalton Thrower, Siemens scored 6 goals with 22 assists and was plus-12 with 91 penalty minutes in 57 games. The Blades finished third in the East Division. Siemens had 1 goal and 1 assist and was minus-two with 10 penalty minutes in the four-game playoff series with Kamloops.
2012-13: Siemens experienced extreme highs and lows in his fourth WHL season with Saskatoon. Expected to be the team captain, that role instead went to 20-year-old Brenden Walker. After getting off to a slow start, the Blades turned things around and Siemens was a big part of that. In 70 regular season games he scored 3 goals with 29 assists and was +31 with 109 penalty minutes. Saskatoon finished first in the East Division but was swept by Medicine Hat in a first round playoff series. Siemens had 1 assist and was +1 with 2 penalty minutes in the series. The Blades hosted the 2013 Memorial Cup and pulled off a shocker – defeating eventual champion Halifax – but were also the first team to be eliminated. In four Memorial Cup games Siemens had 1 assist and 8 penalty minutes.
2013-14: Siemens skated in 46 of 76 games for Colorado AHL affiliate Lake Erie in his first pro season — missing time due to injury and struggling to work his way into the lineup for the Monsters. He scored 1 goal with 3 assists and was -1 with 45 penalty minuets. The Monsters missed the playoffs, finishing fourth in the North Division.
2014-15: Siemens made his NHL debut in the final game of the season, seeing 14 minutes of ice time with no points nor penalties in a game against Chicago. In his second season with AHL affiliate Lake Erie he had 6 assists and was -4 with 57 penalty minutes in 54 games. The Monsters missed the AHL playoffs, finishing fourth in the Midwest Division.
Siemens is a stay-at-home defenseman with a nasty streak. The fact that he is learning from Adam Foote should make any opposing players tremble in their skates. While he is not known for his offensive game he has the ability to contribute on that front.
Siemens is in the third year of his original entry-level contract in 2015-16 and his development has been slower than expected. Now playing for new Avalanche AHL affiliate San Antonio, he is a solid, physical presence for the Rampage. At times he shows flashes of why he was the 11th overall pick of the 2011 draft but at this point his NHL future is still uncertain.