Beane also announced that the club would activate righty Rich Harden before the Friday opener of Oakland's three-game Interleague series in New York against the Mets.
Bradley, a mercurial talent with a troubled past who was acquired by Oakland in a trade with the Dodgers in December 2005 and has been on the disabled list five times since the start of 2006, must be traded, placed on waivers or released outright within 10 days.
"Ultimately, we were going to have a problem with all of our outfielders," Beane said. "This is proactive vs. reactive. ... There was going to be a playing-time issue -- not just now, but going forward."
In addition to having outfielders Mark Kotsay, Shannon Stewart, rookie Travis Buck, Nick Swisher (who also plays first base) and Jack Cust (who has seen most of his action at designated hitter) on the active roster, rehabbing outfielders Chris Snelling and Bobby Kielty are expected to be ready to play within a couple of weeks, and injured designated hitter Mike Piazza has been taking batting practice with the team in preparation for a return that might include occasional catching duty.
"We're not out of the woods yet in terms of roster decisions," Beane said.
Beane met with Bradley, whose contract is up at the end of the season, after Oakland's 5-3 win over the visiting Reds on Wednesday. And while the GM did not offer any details about the conversation other than saying it was "short," he suggested that the development of Buck and the acquisitions of Cust and Snelling played a role in the move.
"Milton sees himself as an everyday player, and he probably is [one]," Beane said. "[But] things changed significantly over the course of the year. ... We're a growth organization, and we always -- all things being equal -- are going to opt for players who are going to be with us for a while."
Bradley, who batted .300 with 11 home runs and 44 RBIs after the All-Star break last season and went 9-for-18 with two doubles, two homers and five RBIs in the American League Championship Series, batted .292 with two home runs and seven RBIs in 19 games this season.
He also made three trips the DL; the first two were the result of a strained hamstring, and most recently he was out from June 3 to June 19 with a strained right calf before being activated for Wednesday's game against Cincinnati.
"When he's been healthy, he's been a productive player," Beane said of Bradley, who missed 51 games with injuries this season, 59 last year, 85 with Los Angeles in 2005 and 61 in 2003. "We don't get to the ALCS last year without him."
Asked if there were any behavioral issues with Bradley, who had run-ins with coaches and the law while with the Indians, feuded with teammate Jeff Kent while with the Dodgers and has gotten into heated incidents with fans throughout his career, Beane said, "No," and later added, "I think he is a good guy."
"We felt like it would be better if we gave him the opportunity to be free," Beane said. "Ultimately, this is what's best for the organization, and hopefully best for Milton."
Beane said he'd had trade talks with at least one club regarding Bradley in the past two weeks, but noted that "it's difficult to have conversations about players on the DL."
Regarding Harden, Beane called his return a "huge boost" and reiterated that while Harden will work of the bullpen, the goal is to get him stretched out for an eventual return to the rotation.
"It'll be a balancing act between getting him ready [to start] again and what our needs are [in the bullpen]," Beane said. "I'm not sure we're completely sure [what Harden's role will be]. We're kind of doing this on the fly."
To replace Bradley on the 25-man roster, Oakland called up infielder Kevin Melillo from Triple-A Sacramento. To make room for Harden, the A's will send righty Shane Komine back to Sacramento.
Originally selected in the fifth round of the 2004 First-Year Player Draft, Melillo, 25, was batting .267 with 21 doubles, six triples, seven home runs, 40 RBIs, a .465 slugging percentage and a .368 on-base percentage in 67 games for Sacramento this season, seeing all of his action at second base.
Mychael Urban is a national writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.