Union head Michael Weiner said last week that arbitration hearings for players contesting suspensions likely would not start until September, which would delay any penalty until next season. But he also indicated the union would urge players to make a deal and get a suspension over with if there was strong evidence of guilt.
"I am deeply gratified to see Ryan taking this bold step," Weiner said in a statement. "It vindicates the rights of all players under the joint drug program. It is good for the game that Ryan will return soon to continue his great work both on and off the field."
Braun's acceptance of the suspension marks a 180-degree turnaround from his defiant spring training news conference in Phoenix last year, after his 50-game ban was overturned.
"We won," he said then, "because the truth is on my side. The truth is always relevant, and at the end of the day, the truth prevailed."
The 29-year-old Braun was hitting .298 with nine homers and 38 RBIs this year, slowed by a thumb injury that limited him to one game between June 9 and Friday. He was at Miller Park before Monday's game against San Diego and addressed the Brewers, then left without speaking to reporters.
"He apologized," pitcher John Axford said. "Whatever else was said beyond that, I don't think we need to carry outside of the clubhouse."
Braun met with MLB investigators in late June. Baseball's probe was boosted when Bosch, who ran Biogenesis, agreed last month to cooperate with the sport's investigators.
The suspension is the latest in a string of high-profile drug cases across sports. Cyclist Lance Armstrong, a seven-time Tour de France winner, ended years of denials in January, admitting he doped to win. Positive tests were disclosed this month involving sprinters Tyson Gay, Asafa Powell and Sherone Simpson.