2007-08: Nathan Lieuwen spent most of the season with the Westside Warriors of the BCHL, but also appeared in three games for the WHL’s Kootenay Ice. He registered a 3.27 goals-against average while posting a .910 save percentage.
2008-09: Lieuwen appeared in just 37 games for Kootenay (WHL) due to concussion issues which prevented him from finishing the season or playing in the playoffs. Lieuwen logged a 2.95 GAA and .885 save percentage and was 14-12 with two overtime losses. Lieuwen played in the 2009 CHL Top Prospects Game, but struggled in Team Cherry’s 6-1 loss. He was ranked 11th amongst North American goaltenders in Central Scouting’s final rankings prior to the 2009 NHL Draft but was not selected.
2009-10: Lieuwen missed much of the season due to post-concussion issues before finally feeling symptom-free towards the end of the season. He appeared in 26 games for Kootenay with Todd Matthews handling the bulk of the goaltending. Lieuwen was 10-10 for the year with a 3.09 GAA and .896 save percentage. He appeared in three playoff games and was 0-1 with a 1.91 GAA while stopping 33 of 37 shots faced. Lieuwen was not among the 30 North American goalies in Central Scouting’s final rankings and was not drafted in the 2010 NHL Draft.
2010-11: Lieuwen assumed the starting role for Kootenay in his third WHL season and after a solid regular season was even better in the playoffs during the Ice’s run to the Memorial Cup. In 55 games during the season he was 33-16 with four overtime losses and three shutouts and had a 2.79 GAA and .903 save percentage. After losing two of the first three playoff games to Moose Jaw in the first round, Lieuwen and the Ice won 15 of the next 16 games. Lieuwen was named WHL Playoff MVP after finishing with a 2.24 GAA and .923 save percentage. In five Memorial Cup games he was 2-3 with a 3.18 GAA and .890 save percentage. In his third year of eligibility he was selected by Buffalo in the 6th round (167th overall) of the 2011 NHL Draft.
2011-12: Lieuwen was one of the WHL’s busier goalies in his final season with the Kootenay Ice — appearing in 57 regular season games and then skating in all four games in the Ice’s playoff series with Edmonton. He was 27-28, with eight losses in overtime, and had 3 shutouts with a 2.50 goals against and .914 save percentage during the regular season as Kootenay finished fourth in the Central Division. He was 0-4 in the series with the Oil Kings with a 3.53 goals against and .896 save percentage. Lieuwen signed a three-year entry-level contract with Buffalo in May, 2012.
2012-13: Lieuwen appeared in four AHL games with Buffalo affiliate Rochester in his first pro season — spending most of the year with the ECHL’s Greenville Road Warriors. He was 1-2, recording a shutout for the Americans, and had a 2.65 goals against and .919 save percentage. Rochester finished second in the North Division and were swept by first place Toronto in the first round of the playoffs. Lieuwen did not play in the series. In 27 games with Greenville he was 14-10-2 with 1 shutout and had a 2.93 goals against and .903 save percentage. Lieuwen was with Rochester during the ECHL playoffs and did not play in the Road Warriors’ series with Kelly Cup champion Reading.
2013-14: Lieuwen made his NHL debut in March after being recalled from AHL affiliate Rochester. He appeared in seven games with Buffalo, recording 33 saves in a 3-2 shootout win over New Jersey for his first NHL win. He was 1-4 with a 2.98 goals against and .906 save percentage. Lieuwen was 17-11-2 with two shutouts and had a 2.34 goals against and .922 save percentage in 32 games for Rochester. The Americans finished second in the North Division and lost to Chicago in a first-round playoff series. Lieuwen did not appear in any AHL playoff games.
2014-15: Lieuwen was hampered by the lingering effects of the concussion he suffered in April 2014 and a hip flexor injury in his third pro season. He played in 16 games for Buffalo AHL affiliate Rochester and was 4-9-0 with a 3.29 goals against and .883 save percentage. The Americans missed the playoffs, finishing last in the North Division.
Lieuwen is a tall, lanky goalie who covers the net with his size and possesses some good athleticism to make saves when caught out of position. He is a very solid goaltender, but his skills are not considered elite and needs to work on his consistency.
Lieuwen has returned to form with the AHL's Rochester Americans in 2015-16. Sharing time with younger prospects Andrey Makarov and Linus Ullmark, he has played well when called upon and handled the bulk of the goaltending chores for the Amerks in his fourth pro season. The 24-year-old has battled physical ailments and is overshadowed by some of the other young goalies in the Buffalo pipeline. His determination in overcoming his concussion issues and getting back in net speaks to his character. If he is not in the Sabres' future plans he could be an attractive backup option for another franchise.