Boston Celtics guard Marcus Smart is sidelined for at least two weeks -- and maybe even longer -- due to a subluxation of the proximal tibfib joint, or what Celtics coach Brad Stevens joked would only be referred to from now on as a "lower left leg injury."

Smart, who already missed three games earlier this season with a sprained big toe, is set to miss a minimum of seven more games with the leg injury. And if he's sidelined through December while rehabbing, it could mean sitting out the other 13 games that Boston has scheduled to close out the calendar year.

The 21-year-old Smart missed 10 games last November due to an ankle injury and two more games in December from an Achilles strain. During summer league play in Las Vegas in July, Smart dislocated two fingers diving for a loose ball and had to heal before returning to basketball activities before the start of training camp.

All of which, fair or not, leaves some wondering if Smart is injury prone. Smart plays hard every possession, and his persistent injury woes reminds some of oft-injured Chicago Bulls guard Derrick Rose (though Smart's injuries haven't been nearly as severe).

We put the injury prone question to Celtics president of basketball operations Danny Ainge.

"Well, hey, listen, when you get injured, it is what it is," said Ainge. "There’s not really much speculation. At age 21, he’s shown the propensity to get injured. That doesn’t mean that that’s going to be a pattern for his whole career, but time will tell on that.

"Marcus is learning -- he’s 21 years old -- and he’s learning how to take care of your body. And how important it is. But none of the injuries are such that they should cause major setbacks. They are all fairly minor injuries, which is good in that they don’t require surgery."

Smart plays with an intensity rarely rivaled on an NBA court. His injury history confirms that he's as likely to throw his body on the ground for a loose ball in summer league as he is in the playoffs. That's just the way he's wired.

It's fair to wonder if the finger dislocation could have been avoided and even Smart isn't quite sure how to explain the freak big toe injury that sidelined him earlier this month. But Smart's ankle injury occurred when he stepped on an opponent's foot and the leg injury was the result of bumping knees with Brooklyn's Thomas Robinson trying to defend a layup (some will argue that Smart didn't necessarily need to be racing back in transition in a lopsided game, but, again, that's just the way he plays).

And now he's forced to be a spectator again.

"[Smart is] frustrated; he wants to play," said Ainge. "He feels like the teams needs him and he wants to help his teammates. He’s frustrated that he doesn’t get to play."

If Smart needs advice on how to endure the notion of being injury prone, he'll find a sympathetic ear in backcourt mate Avery Bradley. It was Bradley who slid to Boston in the 2010 draft in part due to an ankle injury sustained in a pre-draft workout. Bradley's breakout season ended early in 2012 when both his shoulders required surgery. He then missed the first two months of the regular season the next year while rehabbing.

Bradley has endured minor maladies since then but appeared in a career-high 77 games last season. He missed a couple games earlier this season due to a calf injury but was adamant he would fight through it.

Said Bradley at the time: "It’s frustrating, but things like this happen, especially with the way I play. I just can’t worry about it. I just have to continue to stay positive and try to improve as an individual by watching film, and continue to keep my teammates positive. That’s my main focus."

Bradley can help Smart navigate his latest absence, but the only thing that will truly eliminate the questions about whether he is injury prone is an ability to stay on the court.