Walker, hitting .271, batted second and played right field against the Giants. He was placed on the disabled list July 26 with a herniated disc in his neck. He needs one RBI to reach 1,300 in his career.
The Cardinals optioned catcher Mike Mahoney to Triple-A Memphis.
Atlanta Braves: Pitcher Joey Devine's trip through the minor leagues was brief.
Prior to their contest against the Padres on Saturday, the Braves purchased the contract of the right-hander -- their first-round pick in June's draft -- from Double-A Mississippi of the Southern League.
Devine, the 27th overall pick out of North Carolina State, becomes the first Brave to make his major-league debut in the same year he was drafted since Bob Horner went straight to the majors in 1978.
Devine tossed five scoreless innings in just four games at Class A Myrtle Beach before being promoted on July 4 to Mississippi, where he went 1-1 with five saves and a 2.70 ERA. He had 28 strikeouts and 12 walks in 20 innings.
In a related move, the Braves designated pitcher Jim Brower for
Brown has spent the season pitching in relief for Buffalo, where he went 4-2 with a 3.57 ERA and four saves in 45 appearances. Since June 23, he is 3-0 with a 1.32 ERA.
Brown was the player to be named in the trade that sent outfielder Milton Bradley to the Dodgers last season.
Dubois, acquired in a July 18 trade with the Cubs, batted .222 (10-for-45) with two homers and two RBI in 14 games for Cleveland.
Lopez was claimed off waivers from Colorado on Aug. 2. He pitched in one game this season for the Rockies and previously pitched in the majors with Toronto the last two years.
Geary was 1-1 with a 4.15 ERA in 28 games.
Information from The Associated Press and SportsTicker was used in this report.