2006-07: Marshall scored 14 goals with 10 assists and had 6 PIM in 27 games for Noble and Greenough in the New England Prep School League.
2007-08: Marshall finished up his career centering for Noble and Greenough. He scored 25 goals with 26 assists in 29 games, all career-highs. Marshall signed a letter of intent to play for the University of Vermont (Hockey East) in 2008-09.
2008-09: Marshall saw spot duty as a third line center and was the only freshmen to see extended action for the University of Vermont as the Catamounts finished tied for third in Hockey East. After falling to Massachusetts-Lowell in two games in the Hockey East quarterfinals, the Catamounts defeated Yale and Air Force to capture the NCAA East Region title before falling to Hockey East rival Boston University, 5-4, in the Frozen Four semifinals. Marshall was +2 in the Yale game and had an even plus/minus in the 3-2, double overtime win over Air Force. He did not play in the Frozen Four game. Marshall had 1 goal and 3 assists and was + 6 with 12 goals in 24 games for the season.
2009-10: Marshall saw mostly fourth line duty for Vermont in his second season and did not play in either the Hockey East or NCAA tournament games. Marshall scored his lone goal of the season in a 4-1 loss to Maine on October 30 and finished with 4 assists and 16 PIM with a -4 plus/minus. Vermont lost to Boston College, 3-0, in a Hockey East semifinal and Wisconsin, 3-2, in an NCAA West regional semifinal.
2010-11: Marshall skated in 27 of 36 games for the University of Vermont as a junior – missing a month due to injury. Marshall scored 3 goals with 2 assists and was -4 with 4 PMs as the Catamounts finished seventh in Hockey East.
Marshall has the height and skating speed to be a two-way, checking forward but has yet to establish himself in two seasons at the University of Vermont. Marshall entered college hockey straight from prep school and is still working to add the size and strength necessary to compete at that level. Marshall is not an overly skilled player and does not shown a lot of offensive instinct to this point so he is forced to rely on positioning and determination to create scoring opportunities.
Marshall's upcoming junior season will go a long way towards determining whether he is a legitimate pro hockey prospect. When Marshall was drafted as a prep school player, it was with the understanding that he was a long-term project and would take time to develop his physical and tactical skills in college hockey. While he shows determination and possesses a solid work ethic, the production has not yet matched that effort. Marshall's long-term prospects are a bit uncertain at this point. Should he establish himself at the Hockey East level this season, he may one-day become a two-way, checking line forward at the pro level.