Jakubauskas remains an option to start Saturday night's game opposite the Astros' Wandy Rodriguez.
The 31-year-old Jakubauskas was starting at Indianapolis. His upcoming role for the Pirates could be as a starter or long reliever.
Jakubauskas spent the majority of the 2009 season with Seattle, compiling a 6-7 record and 5.32 ERA. He had eight starts in 35 games. The Pirates claimed him off waivers last November.