Rodney, 39, has been inconsistent over the past two seasons. This past season, he was lights-out with the Padres, posting a 0.31 ERA in 28 appearances. After the Marlins acquired him at the end of June, he struggled to a 5.89 ERA in 39 appearances.
Brad Ziegler, who closed for the Diamondbacks in the first half last season, went to the Red Sox in a midseason trade and is now a free agent. The Diamondbacks had six other relievers register a save, but only Daniel Hudson and Jake Barrett recorded more than one. Adding Rodney will give the club some stability in the ninth inning.