SCOTTSDALE, Ariz. -- The first day of Camp Gibby went off without a hitch as D-backs pitchers and catchers worked out for the first time at Salt River Fields on Monday.

"To me, this is probably the most exciting day of the baseball season," general manager Kevin Towers said. "You've been looking at these guys on paper for the last four or five months, but to see them come out and start going through agility drills, full uniform, ready to go -- it's very exciting. This is the start of the journey. This is the start hopefully of a lot of good things for this organization."

The only player absent was left-hander Clay Zavada, who signed a Minor League contract this winter following last season's Tommy John surgery and was invited to big league camp. Neither Towers nor manager Kirk Gibson were anticipating Zavada not being in attendance.

"I don't at this time, no," Gibson said when asked if he knew why Zavada was not in camp.

Towers said that he heard from head athletic trainer Ken Crenshaw that Zavada might have been having second thoughts about resuming his baseball career.

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"He did not show up [Sunday] night for the physicals," Towers said. "I have not talked to him personally, Ken just said that maybe he had some doubts on wanting to go through this again or not. I'll probably lob a call to his agent today just to see what's going on. I don't know the kid very well. It's kind of a surprise for me."

Those who were in attendance got a talk from Gibson prior to the workout during which he told them that the camp was going to be focused on competition and also went through what his definition of a pitcher is.

"Obviously we want to command the zone with all pitches at any time in the game," Gibson said. "We all know that, we focus on that stuff. Fielding your position, being able to control the running game, your sequences, your [pickoffs] and then how to handle the bat."

And by handling the bat, Gibson does not mean just being able to bunt, but also slash -- fake bunt and then swing away -- and even hit-and-run.

Gibson had one other message for the pitchers this spring.

"Don't take things with sensitivity or as criticism," he said.

Zach Duke was in camp on time, one day after Towers said he thought the left-hander might be late because his wife was set to give birth to the couple's first child any day now.

Turns out the baby girl, Madison, was born last week and Duke, who was acquired from the Pirates in November, threw a bullpen session on Monday.

"It was the toughest flight away from my family I've ever had to take," Duke said. "To leave my poor 3-day-old daughter was tough."

Duke's wife, Kristin, will stay in the couple's home near Fort Worth, Texas, until Madison is able to travel in around four weeks.

"She's super mom right now," Duke said of his wife. "I'll tell you what, seeing her through the whole pregnancy, the delivery, everything, I have a totally new respect for my wife and the female body. She didn't bat an eyelash the entire time. I know I would have been crying multiple times, but she's tough."

One of the new additions to the day's schedule that was different than past years was time carved out for signing autographs. Pitchers did it as they finished up their drills while catchers did so after their conditioning.

The new Spring Training complex was designed with fan interaction in mind and spectators were allowed to mingle with players as they moved from field to field. Players will be available for autographs around 11:50 a.m. MST daily.

Gibson said he learned the importance of signing autographs from his first big league manager, Hall of Famer Sparky Anderson.

"They'll sign every day," Gibson said of his players. "That's something that's important. Sometimes when we're young we think we're the most important thing about the game, but the reality is when we leave, the game keeps right on going. [Anderson] would always argue with me that if the fans left the game none of us would be around. They're very important. They're great human beings, they support our great game of baseball and they deserve to be treated with respect as well."