Terms of the deal were not disclosed, but Wickman is likely to remain with Arizona for the rest of the 2007 season, as the NL West-leading Diamondbacks need bullpen depth for the division-title drive.
The 35-year-old Wickman complained of arm pain earlier this summer. His release in Atlanta came as a surprise.
He is 3-3 this season with an ERA of 3.92, 20 walks and 35 strikeouts, He has 20 saves in 26 chances over 43 2/3 innings.
The Diamondbacks did not say specifically how Wickman will be used. Their closer, Jose Valverde, has a team-record 42 saves for the season.
The Diamondbacks designated right-hander Enrique Gonzalez for assignment.