John Mitchell had three points to lead the Marlies over Grand Rapids 5-1 in American Hockey League action in front of 6,088 fans at the Ricoh Coliseum on Sunday afternoon.
A win by Grand Rapids (37-32-6-5) would have clinched the team a playoff berth in its last game of the regular season, but the loss meant the Griffins had to hope the Peoria Rivermen, who had 84 points to the Griffins' 85 entering Sunday's action, did not pick up a point in its game at Milwaukee.
If both teams end up with 85 points, Peoria holds the tiebreaker because it earned more points in the head-to-head battle with Grand Rapids this season.
Jamie Sifers, Robbie Earl, Brett Engelhardt and Michel Leveille added goals for the Marlies (34-39-2-5).
Eric Himelfarb replied for the Griffins (37-32-6-5).
Justin Pogge picked up the win in goal.
The Marlies finished the year in last place in the Western Conference's North Division, while the Griffins finished fourth in the same division.
Marlies captain Marc Moro was named the team's MVP prior to the game. Sifers took home rookie of the year honours, while Staffan Kronwall was named the club's top defenceman.