The Brewers don't plan to put him on the disabled list unless the shoulder does not improve in the near future, but that could change if they must use most of their bullpen in any game this weekend.
Gagne was lifted during the ninth inning of the Brewers' 7-2 win in Pittsburgh on Tuesday night with right shoulder stiffness, allowing Jason Bay's two-run home run, walking two and throwing 26 pitches in his first appearance in a week.
After that game, Gagne said there was no structural damage in the shoulder and that the problem in his shoulder developed during the preceding week when he threw constantly between games to work out problems in his delivery.
With Gagne out, former Pirates reliever Salomon Torres will get most of the Brewers' save opportunities. He lost his job as the Pirates' closer after blowing six of 18 save opportunities last season.
"Our bullpen is what is it right now," manager Ned Yost said. "I'm happy with where it is."
The 32-year-old Gagne, signed to a $10 million, one-year contract to shore up what was an unsteady Brewers bullpen, is 1-2 with a 6.98 ERA and 10 saves in 15 opportunities. He was taken out of the closer's job briefly earlier this month due to ineffectiveness.
Gagne had 152 saves with the Dodgers from 2002-04, routinely throwing from 95 to 98 miles per hour, but was much lower than that while pitching two-thirds of an inning Tuesday.
Gagne had surgery to remove a nerve in his pitching elbow in April 2006 and pitched in only two games that season after elbow problems limited him to 14 games in 2005. He returned to go 2-0 with a 2.16 ERA and 16 saves in 34 games with the Texas Rangers last season, but was a major disappointment after being dealt to eventual World Series champion Boston by going 2-2 with a 6.75 ERA and no saves in 20 games.
Gagne was the 2003 NL Cy Young Award winner.