Souza, 30, missed last season because of a left knee injury after he slipped on home plate and tore multiple ligaments near the end of spring training. Souza's best year was in 2017, when he hit 30 homers for the Tampa Bay Rays. He made $4,125,000.
The 27-year-old Walker missed most of the last two years after Tommy John surgery. The right-hander pitched one inning during the last week of the 2019 season and made $5,025,000.
Joseph, 33, spent a big chunk of the year in Triple-A and played in 20 games for Arizona, hitting .211 in 38 at-bats. He had a split contract calling for $1.1 million while in the majors and $250,000 in the minors.
All three would have been eligible for arbitration had they been offered contracts.