The two will miss the Wildcats' last four games, beginning with Saturday's at Oregon State, senior associate athletic director Kathleen LaRose said. She declined to comment further, citing federal student privacy regulations.
Interim coach Mike Hankwitz, through a department spokesman, declined to comment.
Harris, a 6-foot-1, 211-pound sophomore, had started every game. Used primarily as a blocker, he had three carries for 8 yards and one touchdown this season, and also caught 10 passes for 86 yards.
Jackson is a 6-5, 312-pound redshirt freshman who earned his starting job on Sept. 20 and had started the last five games.
On Tuesday, Hankwitz suspended tailback Clarence Farmer, the Pac-10's leading rusher as a sophomore in 2001.
Arizona (1-7) has lost seven straight games, three under Hankwitz, who was coach John Mackovic's defensive coordinator. He replaced Mackovic when he was fired on Sept. 28.