"This," Beane said on a conference call Friday, "is not something any of us would have envisioned."
Brought back as a free agent to the team that selected him in the 1992 First-Year Player Draft and developed him into one of the game's premier run producers, Giambi, 38, hit 11 home runs with 40 RBIs in 83 games before when he was placed on the DL with a strained right quad on July 20.
At the time, his .193 batting average ranked last among all qualifying Major League hitters, and he had the fourth-lowest slugging percentage (.364) in the American League.
"He struggled," Beane said. "That was the main reason [for his release]."
It certainly wasn't the only reason. With the A's stuck in last place in the AL West and headed for a third consecutive losing season, the club will spend the next seven weeks taking long looks at a number of less experienced players, including 26-year-old first baseman Tommy Everidge, a late bloomer recently called up from Triple-A Sacramento.
Everidge posted huge Minor League numbers before being summoned to Oakland, and he's been on base in each of his 10 games since his promotion.
"Tommy has performed at every level," Beane said. "He deserves the opportunity ... and this is a good opportunity for us to give a lot of guys a chance to play these next two months.
"Professionally, this was the obvious way to go."
It was not the type of homecoming season that Beane and the A's had so publicly hoped for when they re-signed Giambi, who served as the face of the Oakland franchise from shortly after his A's debut in 1995 through 2001, after which he signed a massive free-agent contract with the New York Yankees.
"I talked to Jason quite a bit [before Friday's move was made]," Beane said. "Everyone knows he's a great guy. ... It was difficult because of the person. Jason has a long, successful history here, and he's someone everyone was very fond of -- not just as a player but as a person."
Beane said he'd been talking to Giambi about the possibility of a release as far back as the All-Star break.
"He acted like a professional," Beane said.
Giambi, the 2000 AL MVP for the A's, is in a 43rd-place tie with Duke Snider on the all-time home run list, at 407. He also ranks among Oakland's all-time leaders in several offensive categories, including No. 1 with a .300 average.
A .282 career hitter with 1,319 RBIs and 1,255 walks over 15 seasons in the bigs, Giambi ranks eighth among the A's all-time franchise leaders -- including Kansas City and Philadelphia -- in home runs (198) and 13th in RBI (715).
He ranks among Oakland's all-time leaders in slugging percentage (.531, second), on-base percentage (.406, second), doubles (241, third), home runs (fifth), walks (636, fifth), extra-base hits (446, sixth), RBIs (sixth), total bases (1,949, seventh), runs (640, eighth) and hits (1,100, ninth).
In a statement released Friday night, Am Tellem, Giambi's agent, said: "Jason is 100 percent healthy and definitely plans to continue playing. He is confident he'll be able to contribute to a team down the stretch."
Beane confirmed that the A's are on the hook for the $1.25 million buyout of the 2010 option on Giambi's contract, which called for a $4 million salary this season.
"Jason's one of those guys who will play as long as he possibly can," Beane said, "and my impression was that he was going to try to continue."