Garnett was limited to about 25 percent of Tuesday's practice at Salve Regina in Newport, R.I., the site of the 2007-08 NBA champions' preseason camp.
Rivers used Garnett in drills but didn't test out the 15-year veteran's recovering knee in five-on-five situations. Instead, Glen Davis filled in for Garnett on the first string while K.G. watched the rest of the practice from the sidelines.
"He looked great," Rivers told Projo.com. "I took him out for about 75 percent of the practice and I just told him to sit down. He didn't like that, obviously. But I just think we are going to be together hopefully till mid-June so there is no reason to wear him out right now."
Despite the limited action, the day was a success for the Big Ticket, who played in just 57 games last year, his fewest in one season since 1998-99.
"Everything went well today," Garnett confirmed. "I thought Doc was trying to kill me for a little bit but it was the first day of camp and it being my 15th and everything, it went well. It was fun to get back out there with the guys, go through the drills and just compete."
Meanwhile, backup point guard Tony Allen — who had surgery on his right ankle in June — was held out of practice but participated in drills on the sidelines.