The school released an updated roster Thursday that included both players. As graduate transfers, Abernathy and Renfro are eligible to play this fall rather than sitting out a year.
Abernathy averaged 25.1 yards per kickoff return and compiled 917 yards rushing and 540 yards receiving from 2011-14. He was limited to two games for Cincinnati last season because of heel and hamstring injuries.
Renfro was Maryland's main punter the last three seasons and averaged 41.5 yards per attempt in 2014.
The updated roster doesn't include defensive back Lemond Johnson, who played four games last season. Tennessee athletic department spokesman Jason Yellin said Johnson is no longer part of the team.