CINCINNATI — Randy Johnson was one of three Diamondbacks placed on the 15-day disabled list today as Arizona finalized its opening day roster.

Arizona also put catcher Miguel Montero and infielder Chad Tracy on the disabled list. The three moves were expected.

The 44-year-old Johnson is coming off his second back operation in less than a year. He went on the disabled list retroactive to March 22, and Arizona is hoping he'll be able to pitch when he's eligible to be reinstated.

Montero broke the index finger on his right hand when he was hit by a foul tip during winter baseball in Venezuela. Tracy, who is recovering from surgery on his right knee, took infield practice and ran agility drills last week.

The defending NL West champions open the season Monday in Cincinnati.