The Celtics trail the Cavaliers, 80-72, heading into the fourth quarter.

Early in the third, Kevin Garnett went for the ball and hit LeBron James in the face. James fell to the ground and went to the bench for a timeout. He returned to the game and scored 11 points in the quarter.

Even though they trail, the Celtics did even things up in the quarter. Paul Pierce and Ray Allen hit back-to-back 3-pointers to tie the game at 68 apiece. But they committed two consecutive turnovers and the Cavs quickly went back up by six.

Garnett and Glen Davis both picked up their fourth fouls. The Celtics, however, have a strong advantage at the line. They are shooting 20-for-23 from the line while the Cavs are 19-for-30.

The Celtics trail the Cavaliers, 54-48, at halftime. Both teams scored 30 points in the second quarter.

After Saturday’s practice, Kendrick Perkins said Anderson Varejao was an instigator on the court, and he has proved to be on Sunday. Varejao has scored 15 points and grabbed 6 rebounds off the bench.

Kevin Garnett leads the Celtics with 10 points. Rajon Rondo has posted eight points and six rebounds.

Glen Davis committed another tough foul against the Cavaliers. He practically leapt at Antawn Jamison and knocked him to the ground while shooting a 3-pointer. He picked up three fouls in the first half.

The Celtics are 0-for-6 from behind the arc while the Cavs are 5-for-12.

There is no denying that Shaquille O’Neal is one of the most challenging big men to go up against in the NBA. But in the case of the Cavaliers, Kendrick Perkins thinks they are better suited without him.

The Cavaliers are 6-1 since O’Neal suffered a sprained thumb on February 25 against the Celtics. While it should be noted that wins during that stretch came against the sub-.500 Knicks, Nets, Pistons, and 76ers, Perkins believes that the Cavaliers have more options and speed without O’Neal.

“In my opinion, I think they’re better,” he said after practice on Saturday. “They can run more, you’ve got Anderson Varejao who’s more of an active body, he gets LeBron open a lot, opens up the paint for him, so I think they’re a better team. I mean obviously Shaq could help them, but I think they’re a better, more fast-paced team.”

Even without O’Neal on the court, Perkins will still have hands full in the paint. Anderson Varejao isn’t as big as O’Neal, but he causes problems for opponents in his own way.

“You’ve just got to take him out of the game,” said Perkins. “I think you’ve got to, all the time he’s more of the instigator. I think you’ve got to be more of the instigator when you’re playing against him. You’ve got to hit him first. He’s a guy who flops, gets a lot of calls, takes charges, offensive rebounds, so I think you’ve just got to keep a body on him and play against him hard.”

Varejao is averaging 11.5 points and 8.5 rebounds in two games against the Celtics this season, compared to 8.0 points and 6.0 rebounds from O’Neal.

Over the years, the Celtics have served as a measuring stick for their opponents. A win over the Big Three and Company has signified to many that they have what it takes to run with the best.

“The Celtics get the best game out of everybody they play,” Jamal Crawford said following a Hawks win over the C’s in January. “They are one of the best teams in the NBA and it’s a good measuring stick.”

“I guess it just proves that we should have high expectations and we should continue to work hard and if we play hard – I think that’s the biggest thing,” Steve Nash said after the Suns dealt the Celtics their first loss of the season.

But the Celtics are no longer at the top of the East. On Saturday, they were nine games behind the Cavaliers for first in the conference. That makes Sunday’s game in Cleveland that much more meaningful. A win on the Cavs home court, where the Cavs are 28-4, would be significant to the Celtics.

“I’m looking forward to the game, seeing exactly where we’re at, just going out there and competing,” said Kendrick Perkins after practice on Saturday. “They’re a great team, they’re at home, best in the NBA, just seeing where we’re at. I think it would be a great confidence boost for us if we could go in their home building and get a win.”

Perkins is quick to point out, however, that while a victory in Cleveland would help their confidence, the Celtics are not measurng their success against that of the Cavs. He says that using a game against the Cavs to assess the Celtics performance is like role reversal “in a way,” but the Cavaliers still have a lot to prove too.

“They still haven’t won anything, they’re just the best team in the league,” he said. “They still haven’t done anything we haven’t done, so right now they’re just the best team in the league and we’ve got to go at them.”

The Celtics will play the Cavs at 3:30 on Sunday. The season series is tied 1-1.

Third quarters have been causes for concern for the Celtics this season. The good news for the C’s is they didn’t blow the lead. The not-so-good news for the Celtics is the Cavs got back within one.

The C’s entered the third quarter up eight, 56-48. But the more LeBron James got to the basket, the smaller their edge got. The Cavs trailed just 74-73 heading into the fourth.

James scored 12 points in the quarter and got to the line seven times. (He made four attempts.) Ray Allen led the Celtics with seven points in the quarter, but Rajon Rondo added just one to his total (15 points).

The Celtics have contained James’ teammates so far, but no lead is ever guaranteed with a clutch player on the court late in the game.

Thursday night will be Leon Powe’s first return to Boston since signing with the Cavaliers last summer.

It could also be the first time he plays in over 10 months.

The Celtics still appreciate Leon Powe's dedication during his career in Boston.

Powe tore the ACL in his left knee during Game 2 of the Celtics first round playoff series against the Bulls last season. That was April 20, 2009. He has not played in an NBA game since.

On Tuesday, after months of rehab, Powe was activated into the Cavaliers lineup. While he did  not get on the court, it presented the possibility for him to make his regular season debut against his former team.

Even though he is in a different uniform this time around, those who spent seasons around him expressed their best wishes for his return:

Ray Allen: “I’d be happy for him. I’d definitely be happy for him. I’m just wishing him well because how he injured himself and how everything went, I was so distraught. We all felt bad so I’d be glad to see him just lace them back up.”

Kendrick Perkins: “I’d be excited for him. Just for him to bounce back after the injury, it could have been a career-ending injury. But for him to come back and get a chance to play, I’d be happy for Leon. He’s a great guy. … He works hard. Leon’s a hard worker. He’s all basketball. He doesn’t drink, he doesn’t do any of the club stuff. He’s strictly basketball.”

Tony Allen: “That’s my man. I’m happy for him. If anybody could come off injuries and play, hey, I’m all for it. I hope he gets back to where he wants to get back. That’s my man. We’ve got a friendship that’s going to last forever. He’s a championship teammate, we won it together, we threw champagne together, he understands me.”

Glen Davis: “It means a lot. He’s a great guy, and for him to have an opportunity to play and do some big things, come back from a tough knee injury, I know it means a lot to him. It’s a joy to see a guy bounce back and fight adversity and come back and be able to play. … We won a championship together. We won it together so he’s always going to be a part of that.”

Head coach Doc Rivers: “It’d be nice to see him playing basketball. I’m looking forward to it. I don’t know, except for having gone through the knee injury myself, and he’s gone through it a couple times, what he has had to go through. So I’m really looking forward to him just playing basketball again. It’ll be great. To me, it’ll be a success story  in a lot of ways because a lot of people didn’t think he could ever play again. When he got hurt, I heard that the first time. I said, ‘You clearly don’t know who Leon Powe is. That kid will always be a success story.’”

Powe averaged 6.6 points and 4.2 rebounds over three seasons for the Celtics. Last season he stepped into the starting role in place of an injured Kevin Garnett and Davis. He scored a career-high 30 points and added 11 rebounds against the Grizzlies last March.

Powe’s troubled childhood has also been chronicled as a testament to his dedication to succeed in the NBA. Click here to read more.

A source familiar with the negotiations has confirmed to WEEI.com that former Celtics forward Leon Powe is in Cleveland and will sign a two-year deal with the Cavaliers upon the completion of the second part of his physical on Wednesday.

After establishing himself as a reliable contributor on the Celtics bench, Powe’s future was in question following a string of knee injuries last season. After missing 13 games with a right knee injury, Powe tore the ACL in his left knee during Game 2 of the first round of the playoffs against the Chicago Bulls. He missed the remainder of the postseason.

This summer the Celtics chose not to exercise their option on Powe’s contract, making the injured 25-year-old an unrestricted free agent in a tumultuous economy. According to the source, Powe is expected to return in February. (The Cavaliers will make their first trip to Boston on February 25 for a nationally televised game on TNT.) While he may not have an impact for the first half of the season, a championship contending team like the Cavaliers could benefit from his playoff experience down the stretch.

Powe was drafted by the Denver Nuggets with the 49th pick in the 2006 NBA Draft. The Celtics acquired his draft rights in exchange for a future second round pick. He averaged 6.6 points and 4.3 rebounds during his three-year career in Boston, while posting 5.0 points and 2.8 boards in 25 playoff games.

Powe is the founder of Fresh Start Family Services, a non-profit organization in the Bay Area which provides support and education for children who, like himself, are growing up in the foster care system. He will participate in a series of basketball camps and community events this weekend in California.