Robinson, a projected starter, suffered the injury Tuesday; according to UGA spokesman Claude Felton, Robinson is day-to-day.
Gillard, Robinson's chief backup, dressed for practice Thursday, but was in a green no-contact jersey.
--Sophomore inside linebacker Alec Ogletree was at practice Thursday, but not participating. Details of his injury are not yet known.
--Safety Jakar Hamilton is out with a concussion. Felton said the senior is day-to-day.