The move was made to make room for Ted Lilly, who returns from the disabled list following offseason shoulder and knee surgery.
Samardzija has an 18.90 ERA in four appearances with the Cubs and has issued six walks while striking out only two batters in 3 1/3 innings.
The 25-year-old right-hander began last season at Iowa as the Cubs tested his stamina with an eye toward making him a starter at the Major League level.
By the end of April 2009, however, the Cubs' bullpen problems dictated that Samardzija take on a share of relief duties. He bounced from Iowa to Chicago and back, going 6-6 with a 4.35 ERA in 17 Triple-A starts and one relief appearance. In the Majors, he was 1-2 with a 7.89 ERA in 19 outings, including one start.