The team also transferred right-hander Tim Lincecum from the 15-day to the 60-day DL on Sunday. Manager Bruce Bochy said left-handed reliever Jeremy Affeldt, out with a strained pitching shoulder, would come off the DL on Tuesday.
Bochy was 6-1 with a 2.95 ERA in 43 relief appearances for Triple-A Sacramento. The 28-year-old right-hander made his league debut when rosters expanded a year ago, appearing in three games.
Panik missed 34 games with lower back inflammation. He was batting .309 with seven homers and 35 RBIs before he was hurt.
Lincecum underwent season-ending surgery on his left hip last Thursday.