Miller, 28, was designated for assignment by the Rays on Thursday. He hit .256/.322/.429 with five home runs and 21 RBI over 174 plate appearances. Miller has played mostly first base this season but has plenty of experience in the middle infield as well, helping provide the Brewers with some depth.
Choi, 27, hit .233/.281/.500 with a pair of home runs and five RBI in 32 plate appearances this season. He pinch-hit with a grand slam in his final plate appearance as a Brewer on Saturday against the Phillies.