TUCSON, Ariz. — Randy Johnson called it an audition. He nailed it.

The 44-year-old left-hander, who six months ago underwent his second back surgery in less than a year, threw off the mound today. He pitched in front of manager Bob Melvin for the first time since his final, unsuccessful outing against the Los Angeles Dodgers last June.

Melvin was more than a little impressed.

"He came out throwing bullets the first pitch he threw," the manager said. "As I've discussed before, the arm's not the issue here. I haven't talked to him since he finished, but I think he's probably pretty pleased with the way it went."

Johnson was satisfied with the outing, which he said went much the same as the three bullpen sessions he had before coming to Tucson.

"I'll just do what I'm doing," he said. "I continue to make progress. I'll throw again on Thursday, take three days off and play catch and do all my workouts, and gradually get in to the other little things I'm not doing now. ... The most important thing for me right now is to get on the mound."

He is not taking part in fielding drills.

"Well, I never was going to win a Gold Glove," he joked.

Johnson threw 27 pitches, taking a brief break after the first 12.

"He surprised me," catcher Miguel Montero said. "He was pounding the strike zone and his arm looked great. It's good news for us."

Johnson has undergone surgery to repair a herniated disc each of the past two seasons. Last year, he had only 3½ months to recover before spring training and now believes he rushed back too soon. He also had back surgery in 1996.

The Diamondbacks are hoping Johnson can return to the form he had in a six-game stretch last season, when he went 4-0 with a 2.04 ERA, striking out 51 with only five walks.

So far, so good.

"Man, location, free and easy, I didn't see him moving his back around," Melvin said. "He seemed pretty comfortable out there, so it's a good first step."