The 27-year-old Herrmann appeared in 142 games for the Twins over the past four seasons, batting .181 with six homers and 33 RBI. Defensively, he played in 69 games as a catcher and 36 as a right fielder. He also played in 17 games in left field and two at first base. In the last three seasons with Triple-A Rochester, Herrmann hit .261 with 30 doubles, eight homers and 54 RBI.
The 24-year-old Palka, drafted in the third round in 2013 out of Georgia Tech, hit .280 with 29 home runs and 90 RBI, and struck out 164 times, in 129 games last season for Class A Visalia.