Minnesota has lost a fourth player early.
Junior defenseman Mark Alt will sign with the Philadelphia Flyers, according to Philadelphia Phantoms beat writer Diana Nearhos.
Alt had no goals and seven assists in 39 games for the Gophers this season and will finish his career with 39 points in 117 games.
Alt is the second defenseman from Minnesota that has turned pro this offseason, joining Nate Schmidt, who signed as a free agent with the Washington Capitals.
Minnesota also will be watching Erik Haula, who is in conversation with the Minnesota Wild at the moment, according to the Star Tribune.
NCHC EARLY SIGNINGS
Scott Mayfield, so, D, New York Islanders
Minnesota Duluth (1)
Chris Casto, so, D, Boston Bruins
Nebraska Omaha (1)
Andrej Sustr, jr, D, Tampa Bay Lightning
North Dakota (1)
Derek Forbort, jr, D, Los Angeles Kings
Western Michigan (1)
Danny DeKeyser, jr, D, Detroit Red Wings
BIG TEN EARLY SIGNINGS
Jacob Trouba, fr, D, Winnipeg Jets
Jon Merrill, jr, D, New Jersey Devils
Nate Schmidt, jr, D, Washington Capitals
Zach Budish, jr, F, Nashville Predators
Nick Bjugstad, jr, F, Florida Panthers
Mark Alt, jr, D, Philadelphia Flyers
Ohio State (1)
Chris Crane, jr, F, San Jose Sharks