Choi was optioned to Triple-A Salt Lake City on Sunday.
With C.J. Cron, Jefry Marte and Albert Pujols all capable of manning first base, Choi's roster spot was deemed expendable despite 15 starts there this season. His offensive production has also taken a steep turn for the worse since launching two homers in an Aug. 4 contest, as Choi is just 3-for-25 since then.