The decision likely would be based on distance, marquee players and BCS ranking.
Las Vegas also could take USC from the Pac-12, an opponent Utah State already played this season. Bowls tend to avoid repeating regular-season match-ups.
Las Vegas Bowl executive director Dan Hanneke said Friday night that his committee was awaiting the results of the Mountain West title game before making a decision.
The bowl pairings are scheduled to be announced Sunday afternoon.
But Hanneke also told the Fresno Bee on Saturday night: "It'd be silly for us not to select Fresno State if they won or lost a close one tonight."
Poinsettia Bowl representative Eric Graves told the Tribune that several MAC opponents could be lined up for the Dec. 26 game.
Prime among the candidates is Northern Illinois, which had its BCS hopes trashed by Bowling Green in the MAC title game Friday night.
Toledo and Buffalo were other possible MAC teams vying for the Poinsettia Bowl, Graves said.
If Utah State were to fall past the Poinsettia Bowl, another potential destination would be the Dec. 30 Armed Forces Bowl in Ft. Worth, Texas, against Navy. But sources expected the Aggies not to fall.
Any destination would be a milestone for a program that has gone to seven bowls in its history. The Aggies never have gone to three straight bowl games, a feat they expect to secure Sunday when the bowl match-ups are announced.