The D-backs claimed the 36-year-old off waivers from the Brewers on Friday and he is scheduled to join the team Saturday when the rosters expand.
Ransom began the year in the Arizona organization and played in 17 games for the D-backs before being designated for assignment on May 21. He signed with the Brewers and played in 64 games for Milwaukee, the last coming on Thursday, when he went 3-for-4 with a double and a home run against the Cubs at Wrigley Field.
Overall this season, Ransom has hit .214 with a .705 OPS, 10 home runs and 39 RBIs.
The trade of shortstop Stephen Drew and the balky back of Willie Bloomquist have left the D-backs a little thin at shortstop and third base, and Ransom figures to see time at both positions.
"We just felt we've been a little shorthanded," D-backs general manager Kevin Towers said. "He's very familiar with how we do things here. Can play third, play short, just figured for the next six weeks it was worth a waiver claim."