Infielder Breyvic Valera was optioned to the Redbirds to make room for Sierra, who has played at the Single-A, Double-A, Triple-A and major league levels this season.
Sierra has batted a combined .270 in 101 games this season with Class A Palm Beach and Double-A Springfield. The 21-year-old will be making his fourth recall this season to St. Louis, with which he is 19-for-52 in 13 games.
Valera went 1-for-5 in three games with the Cardinals since making his major league debut on Sept. 5. He hit a team-best .314 in 117 games with Memphis this season.