Righthander Scott Mathieson was placed on the 15-day disabled list with a muscle strain in his back, the Phillies said.
Mathieson, 26, appeared in two games for the Phillies this year with his last appearance coming Sept. 5 against the Milwaukee Brewers.
The Phillies claimed righthander Cesar Carrillo off waivers from the San Diego Padres. To make room for Carrillo on the 40-man roster, lefthander Nate Robertson was designated for assignment.
Robertson allowed six runs last night against the Marlins in a game the Phillies led, 10-0.
Carrillo, 26, went 5-14 with a 5.60 ERA in 27 starts for Triple A Portland this season. He also appeared in four games for Olmecas de Tabasco, of the Mexican League.