The Pirates transferred Choi from the 15-day injured list to the 60-day IL on Sunday.
It's a procedural move by the Pirates to clear a spot on the 40-man roster for utility man Drew Maggi, whose contract was selected from Double-A Altoona ahead of Sunday's game against the Reds. Choi, who is recovering from a left Achilles' tendon strain, is expected to return from the IL in late June or early July.