The Cubs placed infielder Ian Stewart on the 15-day disabled list, retroactive to June 13, and designated catcher Koyie Hill for assignment.
To take their spots on the 25-man roster, Wellington Castillo was activated from the disabled list and Triple-A infielder Luis Valbuena was recalled from Iowa. Both players were available for Thursday's series finale against the Detroit Tigers.
Valbuena, claimed from the Blue Jays on waivers April 4, was batting .303 in 211 at-bats at Iowa. He is a career .226 hitter in the majors, spending parts of four seasons in Seattle (2008) and Cleveland as a utility infielder.
Castillo played seven games with the Cubs this season. He's been on the disabled list since he sprained his right knee on May 22.