To replace Saito on their roster, the Diamondbacks have recalled left-hander Mike Zagurski from Triple-A.
Saito last appeared for the Diamondbacks on Sunday, when he allowed two runs on three hits over one-third of an inning to the Washington Nationals.
Saito signed a free agent deal with the Diamondbacks this off-season. The 42-year-old has appeared in ten games for the club, maintaining an ERA of 6.14 with four strikeouts and three walks over seven and one-third innings of work.
Zagurski has appeared in thirty-two games for Arizona this season. The 29-year-old maintained an ERA of 6.18 with 8.5 SO/9 and 4.6 BB/9 over twenty-seven and two-thirds innings. He was acquired by Arizona from the Philadelphia Phillies this off-season.