Casilla, a 28-year-old middle infielder, has played in each of the last seven seasons for the Twins. The switch-hitter is a career .250 hitter with a .305 on-base percentage in 515 games, and he set personal highs in games played (106) and stolen bases (21) for Minnesota this season.
Baltimore outrighted outfielder Lew Ford, infielder Steve Tolleson and left-handed pitcher Zach Phillips to Norfolk, bringing the team's 40-man roster to 39 players. Five players -- Brian Roberts, Stu Pomeranz, Tsuyoshi Wada, Nolan Reimond and Oliver Drake -- were activated from the disabled list.
Wada, a veteran of Japan's Pacific League, signed with the Orioles last offseason but ultimately needed ligament replacement surgery on his left elbow. Wada, 31 years old, missed the entire 2012 campaign and will rehab to try to make his big league debut at some point next season.
Roberts, the team's longest-serving player, played in just 17 games last season. Roberts started the year late after overcoming the lingering effects of a concussion suffered in 2011 and batted just .182 before being shut down with a right groin strain. The veteran had right hip surgery on Aug. 2.
Reimold got off to a hot start for the Orioles last year -- batting .313 with five home runs in his first 16 games -- before suffering a herniated disk in his neck that ended his season.
Spencer Fordin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.