The Panthers, 15-0 against Alliance opponents, meet Wesleyan, and Bowdoin will face Rochester Tech in the two games.
Middlebury defeated its foremost opponent this season, Rochester Tech by 6-4 and 6-3.
And Rochester Tech (7-0) has outshot its foes, 299-176, and outscored them, 50-19.
Rochester Tech and Plattsburgh are expect to be included later in the N.C.A.A. tournament.
Williams had been ranked fourth in the East region and Rochester Tech sixth before the upset of No. 2 Elmira.
Nazareth, the Super Six champion, and Rochester Tech, the runner-up, assume they will be included again.
Other pairings are Gettyburg at Denison and Rochester Tech at Nazareth.
Rochester Tech (10-0) is off to the best start in school history.
Rochester Tech announced on June 5, 2009 that it planned to leave the Empire 8 for the Liberty League beginning in the fall of the 2011-12 season.
Other powers are Bowdoin, Rochester Tech and Southeastern Massachusetts.