SMU star WR Reggie Roberson Jr. out vs. Memphis with foot injury

McAfee: Gainwell has been an 'absolute stud' for Memphis (0:42)

Pat McAfee breaks down the matchup between SMU and Memphis and explains why Kenneth Gainwell has been a key player for the Tigers. (0:42)

SMU will be without top wide receiver Reggie Roberson Jr. for the Mustangs' showdown at No. 24 Memphis on Saturday night.

Roberson suffered a foot injury in last week's win over Houston and did not travel with the team.

He enters Saturday eighth in the nation in receiving yards with 803 and leads SMU with an 18.7 yards-per-catch average. Roberson's six receiving touchdowns are second on the team.

The AAC matchup between the Mustangs (8-0, 4-0) and the Tigers (7-1, 3-1) could carry huge ramifications, as both have hopes of being the highest-ranked Group of 5 team when the season's first College Football Playoff rankings are revealed Tuesday at 9 p.m. ET on ESPN.

At No. 15, SMU is the highest-ranked team in the AP poll from outside the Power 5 conferences, while Memphis is behind No. 16 Notre Dame, No. 17 Cincinnati, No. 20 Appalachian State (which lost Thursday) and No. 21 Boise State.