Gyorko and Sogard each had $4.5 million options and now instead become eligible for free agency. Gamel remains under team control after the Brewers declined a $2.55 million option on him.
The moves come one day after the Brewers declined a $15 million option on 2011 National League MVP Ryan Braun, whose 352 career homers make him the franchise's all-time leader in that category. Braun, who is due a $4 million buyout, said during the season he was contemplating retirement.
Gyorko, 32, batted .248 with nine homers and 17 RBIs in 43 games and 117 at-bats this season. His .838 OPS was the highest of any Brewers player with at least 60 at-bats. He played mostly against left-handers but became the Brewers' primary first baseman by the end of the season.
Sogard, 34, hit .209 with one homer, 10 RBIs and a .560 OPS in 44 games. He had a .281 on-base percentage and .278 slugging percentage.
Gamel, 28, batted .237 with three homers, 10 RBIs and a .718 OPS in 40 games.