Look at Minnesota's 1939-40 schedule.
12/14/1939 ** London A.C. (ONT)* 10-2* W* * Minneapolis Arena, MN* 3,000* nc*
12/15/1939 ** London A.C. (ONT)* 5-2* W* * Minneapolis Arena, MN* 3,500* nc*
12/29/1939 ** Yale* 3-0* W* * St. Paul Auditorium, MN* 3,500* nc*
12/30/1939 ** Yale* 7-2* W* * Minneapolis Arena, MN* * nc*
1/5/1940 ** Illinois* 8-2* W* at * Champaign, IL* * *
1/6/1940 ** Illinois* 10-2* W* at * Champaign, IL* * *
1/12/1940 ** Michigan Tech* 9-1* W* at * Houghton, MI* * nc*
1/13/1940 ** Michigan Tech* 8-0* W* at * Houghton, MI* * nc*
1/18/1940 ** Michigan* 9-2* W* * Minneapolis Arena, MN* 2,000* *
1/20/1940 ** Michigan* 5-2* W* * Minneapolis Arena, MN* * *
2/2/1940 ** Michigan Tech* 7-1* W* * Minneapolis Arena, MN* 2,500* nc*
2/3/1940 ** Michigan Tech* 9-1* W* * Minneapolis Arena, MN* * nc*
2/9/1940 ** Illinois* 9-1* W* * Minneapolis Arena, MN* 3,000* *
2/10/1940 ** Illinois* 9-2* W* * Minneapolis Arena, MN* * *
2/24/1940 ** Michigan* 7-0* W* at * Ann Arbor, MI* * *
2/26/1940 ** Michigan* 5-0* W* at * Ann Arbor, MI* * *
3/2/1940 ** Amesbury* 9-4* W* at * Lake Placid, NY* * nihc*
3/3/1940 ** Brock Hall* 9-1* W* at * Lake Placid, NY* * nihc*
Just because no other universities made the Gophers playoff schedule doesn't mean other universities weren't involved. Have you considered that those "amateur" teams may have beaten out the other universities for playoff spots? Or, maybe even beaten other universities to advance to face Minnesota in the playoffs?