WALTHAM, Mass. -- Celtics point guard Rajon Rondo was shuttling through the various media day stations Monday when he spotted an assistant coach with a football on the balcony outside the office of president of basketball operations Danny Ainge.

Instinctively, he called for the pass, caught the ball in stride and playfully powered through a reporter on his way off the court.

To the uninitiated, Rondo sure looked like his old self. And after a partially torn ACL ended his season in late January, there were whispers that he would try to make an Adrian Peterson-like recovery and be back on the floor for the start of the 2013-14 campaign. That would have been an aggressive nine-month timeline.

Speaking to reporters for one of the first times since his mid-February surgery, Rondo said he'll be back this season but is taking the process slowly and making sure he's mentally ready first.

He is now participating in basketball-related activities, and will do such when the team opens training camp on Tuesday in Newport, R.I., but he has not been cleared for contact.

One week after Ainge suggested a potential December return for Rondo -- then quickly backed off any timeline talk -- Rondo coyly hinted at a similar December target.

Asked when he plans to return, Rondo quipped, "the 2013-2014 season."

Pressed on that vague timeline, he offered, "Probably sometime in the winter. Maybe the fall."

Winter officially begins Dec. 21.

Rondo said he has chatted with numerous players from multiple sports who have endured the same surgery and rehab, including former Patriots receiver Wes Welker. He also understands that every surgery and every rehab is different and pledged to return to the court only when he is mentally ready, something that new Celtics coach Brad Stevens has echoed since their first meeting in July.

"When I'm mentally ready, I'll play," Rondo said. "Until you go through this type of injury -- a lot of people gave Derrick Rose a lot of heat about not playing, or whatever the case may be -- this injury isn't easy. It's more mental when you come back, and you get around 10-11 months, it's just feeling confident. You want to feel confident, especially the type of players and competitors we are.

"Our legs are pretty much everything, we use our speed; [Rose is] very athletic, I'm athletic. And you need that mental aspect to go up and jump and come down without thinking about your leg again. Because the last jump, for myself and him, we've come down and torn our ACL. Just being mentally ready -- when I get there, I'll play."

Later Rondo noted he'd return when "I feel confident, and I don't think about [the injury], just go out there and play. Even when my knee is going to get hit, or I have to go through a screen, when I don't think about that part of the game with my knee, during the game, I'll be fine. I'll be ready to go."

Ainge hesitated again to establish a timeline with Rondo.

"I can't give you anything but a guess, and I probably won't guess. I'll let you guess. Your guess is as good as mine," Ainge said. "I don't know. He won't be ready [Tuesday for the start of camp]. He'll be on the court. He'll be with the team. He'll be running through all of our non-contact things. He's working out once, twice most days. He's doing therapy. His weak leg is getting stronger. He's doing what he can, and I've been very impressed with his work. I think he'll be back sometime during the season."

While unable to partake in all activities on the floor, Rondo recently invited much of the organization to his house for a team-bonding dinner.

"Rondo had a big dinner at his house the other night," Ainge said. "He invited everybody, the coaching staff, ownership, all the players that were in town. He's been around here, talking to his teammates as he's working out. He goes through most of the drills that he can do and stays away from contact."

In the aftermath of speculation about how he would mesh with Stevens, Rondo talked glowingly of his new coach.

"Me and Brad have become best friends," Rondo said. "We talk every day, we laugh and joke, we just had dinner the other night. I'm going to help him, he's going to help me. He has my full support, and I told him from day one when he came to my camp [in Louisville for their first meeting in July], I'm 100 percent behind him."