Anderson, 33, returns to the Brewers and can make an additional $1 million in incentives.
The deal is pending a physical.
Anderson signed a one-year contract with Milwaukee in December 2019. He went 4-4 in 11 appearances (10 starts) with a 4.21 ERA over 47 innings pitched during the pandemic-shortened 2020 season, missing the Brewers' wild-card series loss to the Los Angeles Dodgers because of a recurring blister issue.
Anderson has been hurt throughout his 13-year big league career. He had back surgery for a herniated disk at the end of the 2014 season and again in 2016 for a bulging disk. He had Tommy John surgery in 2011, and he has missed time with an oblique strain and broken finger.
During the 2019 season, he went 13-9 with a 3.89 ERA in 31 starts with the Oakland Athletics. Despite posting the lowest strikeout rate of any qualifying starter in baseball (just 12.1% of batters faced), he boasted a 2.7 bWAR (Baseball-Reference's wins above replacement) thanks to a low walk rate and the third-best ground ball rate among starters.
For his career, Anderson is 63-65 with a 4.06 ERA and 714 strikeouts in 186 starts and 13 relief appearances for the Athletics (2009-13, 2018-19), Colorado Rockies (2014), Dodgers (2015-16), Chicago Cubs (2017), Toronto Blue Jays (2017) and Brewers (2020).
The Associated Press contributed to this report.