PHILADELPHIA – Someone asked Doc Rivers if this tough-on-the-eyes 82-75 loss in Game 6 of the Eastern Conference semifinals reminded him of a series against Cleveland in 2008 when the Celtics rebounded from a similarly offensively-challenged setback. It was an odd choice considering that team had all of its players healthy and still in the prime of their careers.

Perhaps a better historical marker for this current crew is 2009 when a banged-up squad couldn’t close out a series on the road in Orlando (losing 83-75) and ultimately suffered a 19-point loss at the Garden in Game 7.

It’s a different time, of course, and that team didn’t have Kevin Garnett. But the parallels are beginning to feel eerily familiar as one by one, the 2012 Celtics continue to be ravaged by the effects of injury and time.

Ray Allen gutted out 25 minutes before fouling out with nine points on 4-for-11 shooting. The 76ers decided that they didn’t have to faceguard him wherever he went, but he was still unable to shake free of Philly’s younger defenders and he was a constant target on the other end of the floor.

One game after a 10-point revival, Greg Stiemsma managed only four minutes of time and seemed a step late, which made sense because he said after the game that his injured foot was, “as bad as it’s been,” while supporting it with an ice pack.

Stiemsma said he would be ready to play in Saturday’s Game 7, but that’s more than can be said of Avery Bradley. Amid reports that he will likely be shutdown with injuries to both his shoulders, his return is at best, doubtful.

“It’s what we have, you know what I mean?” Rivers said. “Clearly Avery’s a great defender but he’s not out there. I can’t worry about it. I really can’t.”

Bradley’s absence was felt throughout the second half as the Sixers simply spaced the floor and allowed their penetrating guards – Jrue Holiday, Evan Turner and Lou Williams – to attack the basket at will.

“Their penetration, their ISOs without Avery on the floor, and they were picking who they wanted,” Rivers said. “That’s what I would do. You can’t blame them for doing it. I’m going to give Doug [Collins] a call and say, ‘Listen, none of that.’ We have to do a better job of covering for guys who may not be able to keep guys in front of us.”

The problem, however, is that Rivers is running out of guys. Playing essentially a six-man rotation -- the five starters plus Mickael Pietrus -- Rivers used Rajon Rondo, Paul Pierce and Garnett for almost 66 minutes in the second half. Their depth, thin in the best of times, is for all intents and purposes gone. That also harkens back to 2009 when Brian Scalabrine was playing sixth-man minutes and Eddie House and Stephon Marbury were the only other options.

Here’s where we stop and remind ourselves that it’s foolish to ever count these Celtics out. How many times have Pierce, Garnett, Rondo and Allen beaten back time and defied their expiration date?

“We’re going to go home,” Garnett said. “Confidence is very high. We’ve been here before. We’re very experienced. All out. Nothing less.”

Really, you should expect nothing less from this team. You know they will play hard. You know they will give you everything they have, even if it’s painful to watch at times. But it’s also fair to ask how much more there is to give, and it’s beyond fair to point out that the Sixers are not exactly the best matchup.

“They’re athletic. They’re young. They are very fast. They play with a lot of energy and it’s very difficult for our guys,” Rivers said. “That’s why the regular season against them was hard. That’s why the playoffs have been hard. We knew that coming in: This would be hard because they have a quickness advantage.”

Philly is also a great defensive team, coached by one of the game’s premier tacticians and their strength is the Celtics’ weakness. We’ve known all year that the Celtics struggle to score points and need to be in the right rhythm and pace to generate offense. In Game 6, there was nothing but the dissonant clang of the ball banging off the rim.

They shot 33 percent and even the ones they did make were hard looks. Garnett attempted 20 shots, but all of them were outside the paint. “Even though Kevin had points it wasn’t really the type of points that we needed,” Rivers said.

Pierce scored 24 points, but more than half of them were on free throws after absorbing some hellacious contact in the paint and Game 5 hero Brandon Bass missed 10 of his 12 shots. Then there was Rondo, who was unable to have anything that approximated a Rondo-game. He scored just nine points on 4-for-14 shooting and in a telling statistic, had just six assists and didn’t get his first one until late in the second quarter on a simple entry pass.

“He wanted to play well,” Rivers said. “He wanted to attack early and missed some shots. He probably got caught in between himself. He saw that the offense wasn’t working. He was trying to orchestrate the offense and trying to go and he probably got caught in the middle tonight. It happens. He’ll be better.” 

Collins talked at length between games about trying to stop Rondo and they were finally able to do so by keeping someone between him and the basket at all times. Throughout the series, Collins has had his defense key in on Pierce and Allen, but in this game he turned the focus on Rondo.

“They really clogged the paint up pretty well on him,” Rivers said. “They used other guys to cut off the seams. I thought we hurt ourselves with our pace. It was basically, we walked the ball up the entire game, so we didn’t get any pace. We have to get Rondo running. Yeah, we don’t want Philly to run but we need to run.”

Heading into Saturday there are obvious factors in the Celtics’ favor. They will have two days of rest and they will be at home. They’ve played four Game 7’s in this era at the Garden and won three of them. They’re playing a team that for all of its athletic advantages is still young and inexperienced. The Celtics should win, but absolutely nothing is guaranteed.

“I can’t speak for them,” Rondo said of the Sixers. “I’m not in their heads. There’s only a couple of us that have been in Game 7’s. This is a new series, new group of guys going head to head and it’s been back and forth the entire series. It’s going to be a tough one at home.”