The team also reinstated first baseman Mat Gamel and left-hander Chris Narveson from the 60-day disabled list. Both missed the bulk of the 2012 season following surgery -- right knee for Gamel, left shoulder for Narveson.
Gonzalez was similarly sidelined after sustaining a season-ending right knee injury in May that dashed any chance of reaching the plate appearances he needed to vest a 2013 option with the Brewers.
The Brewers are very unlikely to pursue Marcum or Rodriguez in free agency, but Gonzalez remains a possibility. Assistant general manager Gord Ash said earlier this month that reports of Gonzalez's rehabilitation were "very favorable," and that he had expressed a willingness to return. Ash and Brewers general manager Doug Melvin both seemed open to having discussions later this winter.
Their decision will dictate the 2013 plan for rookie Jean Segura, a shortstop who was the centerpiece of the trade that sent Zack Greinke to the Angels. Segura batted .264 in 44 games after the Brewers called him up in August.
"We love Segura. We think he's a Major League shortstop," Melvin said. "But you know, over the course of a year, you have depth, too. Depth is so important, especially at a position like that."
Added Ash: "What's compelling to me is there are choices now. This time last year, we didn't have choices at that position."
The Brewers' other players eligible for free agency -- pitcher Livan Hernandez and catcher Yorvit Torrealba -- already exercised that right during the National League Championship Series.
In another transaction, infielder Hector Gomez, whom the Brewers outrighted to Triple-A Nashville on Oct. 19, signed a Minor League contract for 2013 that includes an invitation to Major League Spring Training camp.
Players can begin signing with new teams after 11:59 p.m. ET on Friday.