Biscuits outfielder Isaias Velasquez has gone on the disabled list and Montgomery has added right-handed pitcher Matt Buschmann (right).
The Rays purchased Buschmann's contract from the Washington Nationals and sent him to the Biscuits. Velasquez was hit in the face with a flyball Sunday night.
Buschmann was a combined 12-6 with a 6.16 ERA between Double-A San Antonio and Triple-A Tucson in the San Diego system last year. He hadn't pitched this season for Washington.
The 28-year-old, who went to Vanderbilt, was a 15th-round pick in the 2006 draft.