C's-Orlando a biggie on many levels

Just another game? Just one of 82 regular-season contests?

Hardly. Even Ray Allen admitted there will be a playoff-like atmosphere when the Boston Celtics visit the Orlando Magic on Christmas Day (ABC, 2:30 p.m. ET).

Not only is this a matchup of the two top teams in the Eastern Conference, not only is it a nationally televised broadcast on perhaps the NBA's marquee day, but there are also leftover emotions from a memorable seven-game series in the Eastern Conference semifinals this past May that helped propel the Magic to the NBA Finals.

"I do [think it's a playoff preview]," admitted Allen, who wasn't bashful about pondering potential implications for home-court advantage in the postseason, particularly with Orlando already boasting a win over the Celtics in Boston on Nov. 20. "We look at it as a game we want to win. When you get to the end of the year, these are the type of games you look back at [for motivation and strategy] before the playoffs."

A little more than a month removed from the first of four regular-season meetings, plenty has changed for both sides, particularly as two-thirds of Boston's Big Three battle the injury bug. That's where we start a comprehensive look at Friday's holiday blockbuster:

What's changed

The Celtics and Magic are headed in different directions healthwise.
While the Magic welcomed back All-Star guard Jameer Nelson earlier this week, the Celtics saw Paul Pierce skip the trip to Orlando after undergoing arthroscopic irrigation on his right knee Wednesday. And Kevin Garnett missed Tuesday's contest against the Pacers with a bruised right thigh, but is expected to play Friday.

Nelson returned to the court Monday against Utah for the first time since undergoing surgery to repair torn cartilage in his left knee on Nov. 18. After a quiet performance (two points in 14 minutes) in a reserve role that night, Nelson rejoined the starting lineup Wednesday against the Rockets and erupted for 15 points, 4 assists and 4 rebounds in 29 minutes.

"Oh, little Mighty Mouse is back! Just happy to see him back on the court, happy just to see him healthy," Orlando center Dwight Howard said. "He has to get back into the flow. I told him [Wednesday], 'Just play. Don't worry about mistakes or missing shots or whatever.
Just go out there and do what you do. We know that you're not going to be perfect, none of us are. But if you go out there and just play, things are going to happen for you.' And he did it."

Said Nelson after Wednesday's win: "Like I told you all last game, whatever minutes they give me, I'm going to play them as hard as I can."

The Celtics, meanwhile, have been rattled by injuries since Celtics coach Doc Rivers scratched Garnett from Tuesday's win over the Pacers. Garnett is nursing a bruised right thigh sustained in a win over Memphis on Dec. 14. He practiced with the team on Thursday, and is expected to start Friday.

Boston needs a healthy Garnett more than ever after Pierce's knee acted up in the hours following Tuesday's game, forcing him to have the draining procedure Wednesday as his teammates traveled to Orlando. Pierce could miss the next two weeks.

Boston is also without reserve guard Marquis Daniels, who earlier this month underwent surgery on his left thumb to repair torn ligaments. On Wednesday,
the team recalled second-year forward Bill Walker from the Maine Red Claws of the NBA Development League to add a healthy body on the trip.

The Celtics might also have Glen Davis back in the lineup soon. Davis, out all season with a broken hand suffered in a fight with a friend, practiced with the team on Thursday. However, the Celtics haven't said when he'll see game action.

Last meeting

The Magic limited Boston to a season-low 34.5 percent shooting while opening a 16-point first-quarter lead as the Celtics registered a mere
13 points in that opening frame. Boston made it a game again, but Vince Carter scored 10 of his 26 points in the fourth quarter to lift the Magic to a 83-78 win at the TD Garden.

Pierce scored a team-high 21 points, while Garnett added 13 points and
11 rebounds in the Celtics' third loss in four tries. Boston struggled mightily from long distance, connecting on only 2 of 19 3-pointers, including an 0-for-8 performance from reserve forward Rasheed Wallace (9 points, 13 rebounds).

Howard (9 points, 15 rebounds) and Rashard Lewis (16 points, 10
rebounds) helped pace the Magic, but Mickael Pietrus really stung the Celtics early. He made 5 of 6 field goals, including all four 3-pointers he attempted, for 14 points.

Winning ways

The Celtics have won 13 of their past 14 since falling to Orlando, including 11 in a row before being tripped up by Philadelphia on Friday. The Celtics have since won back-to-back games at home (Minnesota, Indiana) and will look to improve upon a league-best 12-1 road mark.

The Magic boast a 12-4 record since topping the Celtics in Boston, stumbling against Utah, Phoenix and Miami (twice). Orlando has won five of its past six overall.

Freaky Fridays

Four of the Celtics' five losses during the 2009-10 campaign have come on Friday. Boston is 3-4 (42.9 winning percentage) on Fridays and 19-1 (95.0 winning percentage) every other day of the week. Rivers joked that he needs to "find out what's going on Thursday nights," because his team has been so sluggish on Fridays. But the truth is the Celtics have faced their top competition on this day of the week and will continue that trend on Christmas.

Key matchup: Nelson versus Rondo

Rajon Rondo had one of his worst games of the season in the Celtics' and Magic's first meeting, struggling against veteran fill-in Jason Williams. Rondo finished with six points (on 3-of-11 shooting), six assists and a team-worst minus-14 in the plus/minus category (matched by center Kendrick Perkins).

With Nelson coming off knee surgery, can Rondo take advantage of his speed? Maybe force Orlando to lean on its backups if Nelson shows any signs of being unable to keep up? The Celtics average five more assists per game than the Magic (24.4 to 19.4) and will need to rely on Rondo to set up easy baskets to alleviate the scoring woes from the first matchup.

Revenge factor?

The Lakers were hell-bent on revenge when they posted a 92-83 triumph over the then-defending champion Celtics last Christmas at the Staples Center. Said Lakers guard Sasha Vujacic afterward: "We've been waiting for that opportunity for a long time, and we won. I don't like them at all. A lot of people called us softies or whatever. It doesn't matter at all. We know what we can do. ... Last year, they won the championship. This year, it's our year, we want to take it all the way."

It will be interesting to see whether the Celtics rally around the same revenge mentality, taking the "these guys prevented us from a chance to repeat" approach. The Celtics are also in the midst of a five-game stretch that features three matchups against teams that have beaten them this season. Boston already has atoned for a loss in Indiana with Tuesday's win and will now be seeking revenge against the Magic (and, later this trip, the Suns).

Playoff recap

Take a stroll down memory lane and relive last season's epic playoff battle at our
2009 NBA Playoffs archive

The bottom line

A glossy Christmas Day matchup has lost a touch of its luster without Pierce, but after the playoffs last season, the Celtics know far too well that injuries are an unavoidable part of the game. Regardless of the personnel on the floor, Boston simply needs to play better than it did in the first outing. The Celtics dug themselves a 16-point hole with their worst quarter of basketball of the season, then rallied to tie the game with less than three minutes to play. They couldn't pull ahead, though, going scoreless in the final 2:54.

As early as that game, Rivers noted that the Celtics won't beat quality opponents without a 48-minute effort. After that initial loss in November, Rivers said, "We're not a 48-minute team yet. We'll get there, and we're going to keep working on it. But I don't think it's as easy as saying we've just got to get off to a better start. I don't think that's the answer. It's clear that we do, but to me it's the [entire] game."

Without Pierce, the Celtics will need others to step up and replace not just his production on the court but also his leadership and vocal direction. Boston might not emerge with a win, but there is potential to learn from this experience. In the same way that the team watched Glen "Big Baby" Davis blossom without Garnett's services in last season's playoffs, the Celtics are hopeful one of Pierce's replacements will take ownership of his position and further strengthen the team's depth for when it matters late in the season.

Chris Forsberg is a roving reporter for ESPNBoston.com. Follow him on Twitter.