Kevin Garnett injury déjà vu for Celtics

Almost exactly one year ago, during the Boston Celtics' second game after Christmas, forward Kevin Garnett got kicked in his right leg during a tilt with the Golden State Warriors, suffering a hyperextension near his surgically repaired knee. The injury sidelined him for 10 games, but combined with other maladies the Celtics were battling at the time, it forced Boston to begin employing what came to be dubbed "strategic rest" while playing .500 ball over the final 54 games of the 2009-10 season.

Wednesday night, during Boston's second game after Christmas, Garnett's right leg bent awkwardly while going up for a two-handed jam against the Detroit Pistons, and he suffered what the team termed a lower leg muscle injury. Celtics coach Doc Rivers told reporters after the 104-92 loss in Detroit that the ailment is likely to sideline Garnett for a period of games, but was initially uncertain exactly how many Garnett would miss.

Time to buckle our seatbelts for another winter ride on the Celtics' regular-season roller coaster?

An MRI on Garnett's leg Thursday will go a long way toward answering that question, but judging by the fact that Rivers deemed himself "not that concerned" by the injury, Celtics Nation can breathe a sigh of relief … for now.

You could hear (and feel) the collective gasp across New England (and probably every other NBA city) when Garnett crumpled to the floor Wednesday night after hobbling his way to midcourt and forcing an intentional foul to stop play late in the first quarter.

With Garnett grabbing at the region near that surgically repaired right knee (Garnett had bone spurs removed in May of 2009), many feared the worst, including Rivers. But by the end of the night, the Celtics were suggesting a muscle injury around the calf that would be far less daunting than any sort of ligament damage to the knee.

Here's one thing to keep in mind, though: Garnett missed only 10 games last season because of the hyperextension, with Boston posting a 4-6 mark without him. With others such as Paul Pierce and Marquis Daniels also sidelined, the Celtics lost eight of 12 after Christmas and 11 of 17, ultimately stumbling through a 27-27 stretch over the final 54 games and securing an unheralded fourth seed in the Eastern Conference.

Considering that Boston is currently playing without Rajon Rondo, Kendrick Perkins and Delonte West, there's reason to wonder how they'll fare if Garnett is also sidelined. The Celtics just got Jermaine O'Neal back on Christmas Day and are hoping to have Rondo on the floor for Friday's New Year's Eve showdown against the New Orleans Hornets.

"Usually without Kevin, we have everyone else," Rivers told reporters. "As Paul [Pierce] said, 'How many more can we take?' If Kevin misses games, we're without Kevin, Rondo, Perk, Delonte. The list is getting really long. I don't think anyone will feel bad for us."

Despite dropping two out of three games on this brief holiday road trip, the Celtics still boast a 24-6 record overall, tops in a beefed-up East. But as the NBA schedule launches into overdrive in January, can the Celtics get by without Garnett?

The Celtics added depth to their frontcourt this offseason, bringing in Shaquille O'Neal, Jermaine O'Neal and Semih Erden for moments like this. But 38-year-old Shaq can be used only in small doses, Jermaine O'Neal missed 19 consecutive games because of lingering knee soreness and is still finding his legs, and Erden didn't play during this road trip due to a stomach bug (a pulled groin limited him before that and he has a lingering shoulder issue).

That means an even more elevated role for Glen Davis, whom the team is already leaning hard on as a sixth man (a spot in which Rivers would like to keep Davis, particularly on an otherwise inconsistent bench).

But Garnett's loss, no matter how short, will almost certainly hurt the Celtics. According to ESPN Stat & Information, the Celtics are 169-57 with Garnett -- a 74.8 winning percentage -- and 33-16 without him, a 67.3 winning percentage. The chief reason for that? The Celtics give up more than six more points per game (98) without Garnett as opposed to with him (91.7). Teams shoot nearly 2 percent better without Garnett on the floor (43 percent with Garnett; 44.8 percent without him).

The Celtics' numbers actually jump up offensively without Garnett (99.8 points per game with him; 101.9 points without him), but the defensive lapses pull that winning percentage back to Earth.

"I know what we lose: We lose a big part of our defense," Rivers told reporters. "[The Pistons] shot [55.7] percent … It's not just [Garnett's] man, it's the entire defense. Unfortunately, [Detroit] proved that."

After a win over the 76ers on Dec. 22, Rivers was asked about whether he feared another post-Christmas skid. He suggested he wasn't so long as Boston could stay healthy.

Losing Garnett won't ease those concerns. No one wants another batch of "strategic rest," but it did lead the Celtics to the cusp of Banner 18 last year. Boston won't hesitate to limp through the next four months if it can assure Garnett & Co. are healthy for mid-April.

Chris Forsberg is the Celtics reporter for ESPNBoston.com. Follow him on Twitter.