Pennington had been at Class A Advanced Inland Empire on a Minor League rehab assignment. He exited a game against the Cardinals on May 12 with what was originally called a cramp in his left hamstring. He was officially placed on the disabled list with a left hamstring strain. Pennington is hitting .217 in 46 at-bats this season.
Ryan was acquired from the Nationals on May 10 to shore up depth at the shortstop position after Andrelton Simmons suffered a left thumb injury. Ryan was used primarily as a utility defensive player, and could never find his rhythm at the plate. He was hitless in 11 at-bats with the Angels.
Ryan became expendable through the recent play of Gregorio Petit, who has assumed the everyday starter responsibilities at the position in Pennington's absence. Petit's hit .267 in 14 games with the team, including going 1-for-3 with a double and a walk with two runs scored Friday.
"Cliff [Pennington] is ready," manager Mike Scioscia said of the move. "Gregorio Petit has been playing tremendous baseball, so we want to keep him with us. He gives us a lot of versatility and depth, so we want to keep him on our roster."
Fabian Ardaya is a reporter for MLB.com based in Anaheim.