[9] He was held scoreless with a -3 plus-minute in three postseason games as the first-place HV71 was swept from the first round of the playoffs by Allmänna Idrottsklubben (AIK) in an upset.

[6] Despite ranking third in the league, HV71 was eliminated from the playoffs in five games against Linköpings HC, during which Fast recorded five points (1 goal, 4 assists),[4] and a +4 plus-minus.

[18] Fast was the fifth of six players the Rangers drafted in 2010, along with Dylan McIlrath, Christian Thomas, Andrew Yogan, Jason Wilson and Randy McNaught.

[19] On 29 May 2012, the Rangers announced Fast had been signed to a two-way, three-year entry-level contract,[7] valued at $2.145 million, with a $900,000 annual cap hit.

[20] When the media asked about the Rangers organization's plan for Fast, head coach John Tortorella replied: "There isn't one.

[25] Although it was his first North American professional training camp, Fast made the Rangers roster,[26] partially because the team needed a right-handed shot to replace the injured captain Ryan Callahan.

said Fast needed to adjust to the smaller North American ice surface, and did not get sufficient minutes to do so quickly enough to remain in the NHL.

[27] Fast scored his first goal of the season on 26 December notching the game winner on the power play against Bridgeport Sound Tigers goalie Anders Nilsson.

[6] Fast marked a North American single-game career high with three points (2 goals, 1 assist) in Hartford's 3–2 win over the Norfolk Admirals on 6 April,[27] earning him First Star of the Game.

[6][15] Fast was a staple on the Wolf Pack's penalty kill unit,[33] and played most of the season on a line with J. T. Miller and Ryan Bourque.

[26] He recorded his first career NHL playoff point with an assist in Game 1 of the Metropolitan Division Semifinal against the Philadelphia Flyers on 17 April.

[41] Fast scored his first NHL regular season career point on 23 November with an assist on Dominic Moore's goal against the Montreal Canadiens.

[51] Fast had played most of the season on the fourth line, often with Moore and Tanner Glass,[52] or with Hagelin and Kevin Hayes,[37] and had been an occasional healthy scratch.

[53] Fast finished the regular season with 14 points (six goals, eight assists) in 58 games,[54] and had been promoted to a top six forward role by the playoffs,[2][54][55] playing on the second line with Kreider and Derek Stepan.

[63] In 2009–10, Fast skated in ten international matches for Sweden at the U18 and U19 levels, but did not participate in the World Junior Ice Hockey Championship tournament.

[5] He scored one goal and one assist in four games for Sweden at the U20 USA National Junior Evaluation Camp in Lake Placid, New York.

[6][7] At age 18, Fast represented Sweden in the 2011 IIHF World U20 Championship,[7][8] where he tied the team lead with four goals in six tournament matches, also recording two assists and a +4 plus-minus.

[6] Fast is considered a skilled forward with good skating ability, hockey sense, and speed,[1][5][25][27] the latter of which gives him an edge in retrieving pucks along the boards.

[33] Alain Vigneault has praised his work ethic and dependability,[36] and former teammate Tanner Glass has noted his ability to make responsible decisions and skillful plays with the puck along the defensive zone wall.

[52] One of Fast's drawbacks is he lacks the ideal frame for National Hockey League play,[1] but his physical game improved after he added muscle in the 2014 offseason.