Rajon Rondo describes breaking hand

WALTHAM — A throng of reporters looked on with raised eyebrows at Celtics media day Monday, many skeptical of how exactly Rajon Rondo broke a bone in his left hand.

Questions were fired asking for more details. At one point, the Celtics star point guard asked, “Am I under investigation?” He was joking, possibly.

Rondo said he broke his hand when he slipped in the shower at his home last Thursday, despite speculation that the injury occurred during a visit to a trampoline park.

“Certain falls happen and you slip, and I slipped and tried to catch my hand,” he said while wearing a black sling on his left arm at the Celtics’ practice facility.

“It wasn’t like a banana [peel] slip. I actually almost caught myself. I landed on my knuckle on the window sill in my home. That’s what happened.”

Rondo said doctors have told him he’ll be sidelined for 10 weeks — though team physician Brian McKeon said it could be eight weeks — meaning he could miss the first month of the regular season, which begins Oct. 29. The Celtics open training camp Tuesday.

“We’ll be very cautious with him,” said Celtics president of basketball operations Danny Ainge. “I think people underestimate how much you use your left hand, not just dribbling and passing — he uses it a lot — but defensively and we want to careful and make sure there’s nothing long term there.”

Facing a barrage of questions, Rondo offered a detailed itinerary of the days leading up to his injury. He said that he visited a trampoline park on different days with his children, but that he didn’t jump at the park on the day he hurt his hand.

“I just let my kids play and run off some steam,” he said. “It was a school night so I wanted to go about 45 minutes. People were really nice there; they let me in for free — that was good. That night, I went home and that’s when the incident happened. It didn’t happen at all at the trampoline place.”

Ainge sat beside Rondo on the podium and said he wasn’t skeptical about Rondo’s injury.

“What makes this story even more unique was, this summer, I was in Vegas and I was staying at the Wynn hotel. I came out of the shower and slipped, and smashed my head,” Ainge said. “I had to go to the emergency room and get my head glued. I spent the night at the emergency room. I guess it’s not so shocking to me that that’s possible.

“Talking to our medical staff, it’s an injury that does happen when you land,” Ainge added. “It’s not like a hitting injury, or a hitting-a-wall injury, or something like that. It’s an injury that usually happens in the third metacarpals.

“I had no reason to not believe Rajon. I’ve been with him now for eight years and he’s never lied to me — that I’m aware of. I have no reason to not believe him.”

Ainge said they wouldn’t look into the matter further, either.

“We’re not investigators,” he said.

Rookie guard Marcus Smart is expected to play considerable minutes filling in for Rondo.

“It’s an opportunity for Marcus,” said Celtics coach Brad Stevens. “It’s an opportunity for Phil Pressey, an opportunity for Evan Turner, it’s an opportunity for all those guys. The only answer that I have for that is that time will tell.”

Smart, the No. 6 overall selection in June’s NBA draft, played point guard at Oklahoma State and will play shooting guard for the Celtics as well.

“If [Rondo] was [here], I’d still have to earn my stripes,” Smart said. “Regardless if he’s here or not, I’m still going to work hard and earn the respect of these guys.”

The injury marks another health-related issue for Rondo, who spent last season working his way back from a major knee injury suffered in January 2013.

“The frustration was that day [of the injury] but the last couple days, I’ve been fine,” Rondo said. “I’ve been pretty positive. I think for what I went through with my ACL, this is nothing.

“I don’t think it’ll be a setback. I think my timing will be off a little bit, but it won’t take long.”

Though he will miss training camp for the second straight season and spend several games encouraging his teammates from the bench, Rondo did offer immediate support of Smart.

“He’s a good, hard-nosed kid,” Rondo said. “He plays extremely hard. He does the intangibles. If you watch him from the sideline, you may not know exactly what he does or brings on the court, but when you play with him, he’s a really strong defender.

“He can rebound the ball. He never gives up on a play. He chases down blocked shots. He’s very athletic and he plays hard.”

And as for himself, Rondo said, “I’m still looking forward to the season. I have high hopes.”

Rondo picked up his cellphone after taking questions from reporters.Elise Amendola/AP