"I was very disappointed yesterday when I learned the extent of my hand injury," Hill said. "I am going to take some time off from baseball activities to let the break heal before starting the rehab process. I am committed to do everything in my power to return to the lineup as soon as possible."
Hill entered the season coming off a stellar 2012 campaign in which he hit .302 with 26 home runs and 85 RBIs en route to becoming the first Arizona infielder to earn a Silver Slugger Award. He was off to a strong start, hitting .306 with two homers and six RBIs in 10 games.
Gregorious, 23, hit .387 (12-for-31) with two home runs and two RBIs in seven rehab games with Triple-A Reno. Acquired from the Indians during the offseason, Gregorious -- ranked the D-backs' No. 3 prospect by MLB.com -- started the season on the DL with a strained right elbow.
"It is really unfortunate to lose not only a talented baseball player but a tremendous teammate in Aaron Hill for the near future," said general manager Kevin Towers. "We are confident that the depth we have in the middle infield will serve us well while Aaron recovers."
Paul Casella is a reporter for MLB.com. Follow him on Twitter @paul_casella. This story was not subject to the approval of Major League Baseball or its clubs.