The Oakland Athletics placed right-hander Santiago Casilla on the 15-day disabled list Saturday because of a sprained right knee, and recalled left-hander Gio Gonzalez from Triple-A Sacramento to take Casilla's spot in the bullpen.
Gonzalez was in uniform and available for Saturday's game in Seattle.
Oakland manager Bob Geren also said before Saturday's game that an MRI on second baseman Mark Ellis revealed a strained calf and that Ellis is expected to miss four to six weeks. Ellis was placed on the disabled list Wednesday.
Casilla became the fourth A's player placed on the DL in four days, and his move was retroactive to April 29. Before getting injured, Casilla had not allowed a run in his last seven outings.
Gonzalez was 1-0 in four starts at Sacramento with a 2.12 ERA.