Corbin (elbow) threw his first bullpen session Tuesday since having Tommy John surgery last March, the Arizona Republic reports. The session Tuesday included 20 pitches -- all fastballs -- and Corbin is expected to progress through adding changeups before working breaking pitches back into the mix. The Diamondbacks are hoping to get Corbin back into their rotation in June, which will likely follow a complete 30-day rehab assignment in the minor leagues as he stretches out following the long absence.