Grimes, a junior, led the Rebels last season with 44 receptions for 696 yards and seven touchdowns but has not played in the first two games this season. Grimes transferred to UNLV from Southern California.
"Randal Grimes is not with us for team or school rules," Arroyo said. "I'll keep the terms of that in-house out of respect for him as an athlete."
In addition, Arroyo said that because of the coronavirus pandemic, wide receiver Mekhi Stevenson, defensive backs Drew Tejchman and Greg Francis, and fullback Jamaal Neal have opted out of the rest of the season. He noted, however, that they "are currently still part of the team."
The Rebels (0-2) host the Fresno State Bulldogs (1-1) on Saturday.