Al Horford stood on the sideline during the first day of training camp Tuesday, tugging anxiously at his No. 15 jersey while his teammates went through a five-on-five drill.

The Atlanta Hawks center can't wait to mix it up again.

Not yet.

The Hawks are playing it safe with Horford, trying to cut down on the risk of another injury like the ones that kept him out for the better part of two seasons. He will gradually ease his way into contact drills, perhaps play a couple of preseason games, all with the focus on being ready to go in the Oct. 29 opener at Toronto.

"The coaches and trainers just want to be safe," Horford said after the opening session at the University of Georgia, where the Hawks are spending the first three days of camp. "I'm very competitive, so I really want to be out there. But we have to be smart about this. I'm taking my time."

Make no mistake, the Hawks desperately need Horford to make it through an entire season if they're going to have any chance of moving up in the Eastern Conference.

"We're fortunate to have him," coach Mike Budenholzer said. "You can just keep talking about the things he does well. That's what makes him one of the most unique and versatile bigs in our leagues."

Now, to keep him on the court.

Horford has missed big chunks of playing time because of two similar but freakish injuries less than two years apart. In January 2012, he tore his left pectoral muscle and wasn't able to return until Game 4 of a playoff series against the Boston Celtics. Last season, Horford sustained a similar injury, this time to his right pectoral muscle on the day after Christmas, and missed the rest of the year.

Not surprisingly, he's a little skittish about coming back this time.

"It's going to be interesting," Horford said. "When I see the guys going here live, and going pretty fast, I definitely wonder. But I feel that once I get out there and the first situation happens where I get hit or have to go and wrestle or something (for a loose ball), once I get through that, I should be fine."

Pairing Horford with All-Star Paul Millsap will give the Hawks a pair of players who are virtually interchangeable at the center and strong forward positions. That should open up more offensive options — something that plagued the Hawks in the fourth quarter last season, especially in their playoff loss to top-seeded Indiana — and tighten up things at the defensive end, as well.

When the subject is the 6-foot-11 Horford, the normally tight-lipped Budenholzer is not at a loss for words.

"He has such an impact on the game in so many different areas," the coach said. "Defensively, he can protect the rim, he can still come out and play pick-and-roll defense, he can switch. He's just a really unique defender.

"And," Budenholzer went on, "it's kind of the same thing offensively. He's very versatile. He's very, very good at scoring in the paint, finishing at the basket. He's a very good mid-range shooter. We're encouraging him to extend his range. He's a good decision-maker with the ball. He can bring the ball the length of the court."

The injuries forced Horford to change his workout routine. His doctors felt the torn pectoral muscles were actually years in the making, the scar tissue building up through countless hours spent in the weight room.

"In college, I did a lot of bench presses, a lot of heavy upper-body lifting and overheads, stuff like that," Horford said. "I had to change all those type of lifts. Now, I'm doing more body weight, focusing more on my core and legs."

Horford said the second injury was a bit easier to accept than the first one. He used the time away to work on areas of the game that he felt needed improvement, to get more comfortable in Budenholzer's offensive system, to become more assertive when the ball is in his hands.

"Putting the ball on the floor, rolling hard to the basket, finishing with contact around the rim," Horford said. "I feel like I'm going to be better from this."

___

Follow Paul Newberry on Twitter at www.twitter.com/pnewberry1963