The move with Aybar is retroactive to April 10. He has missed the past four games because of a bruised left heel.
Jepsen is sidelined because of a strained triceps. He last pitched on Thursday night. The six-year veteran has faced 17 batters and allowed four runs and two homers in 3 2-3 innings.
Shuck rejoined the big club one day after he was optioned to make room on the roster for infielder Luis Jimenez, and batted leadoff on Saturday.