WALTHAM – The Celtics have a problem and his name is LeBron James, but that’s far from the only thing that concerns them heading into their conference semifinals matchup with the Cavaliers. 

It’s not just that James can score, which is a big enough worry. It’s not even that he can, and does, pass. It’s that when he passes it’s to a bevy of 3-point shooters. Or it’s to a collection of jump shooting big men. Or it’s to a rolling big flying down the lane toward the rim. 

The Celtics have already dealt with one superstar in the playoffs, but unlike Dwyane Wade, LeBron won’t be dishing off to the likes of Quentin Richardson and an aging Jermaine O’Neal. The Cavs may not have superstars around James, at least not superstars in their prime, but they do have a vast assortment of capable role players that compliment his skills. 

“The 10 [rebounds] and 10 [assists] we can’t have,” Doc Rivers said after a two hour practice Thursday. “The 30 and the 40 [points] we don’t want, and if he has it we want him to have it our way, not his way. That upset with us with Wade in a couple of games.” 

And don’t pay any attention to the breathless reports about LeBron’s elbow that have kept Cleveland on edge the last few days. 

“I figure this,” Paul Pierce said. “LeBron with a bad elbow is still better than 95 percent of the league.” 

Pierce will have the primary responsibility of guarding James. He will have help, of course, but Pierce is the first line of defense. 

“I think it’s his strength more than anything,” Pierce said. “I get a lot of help on the interior, but you got a guy that’s so strong, once he gets in the paint he’s able to just take and absorb the bumps from not only me, but the big men, and still get the shot off and get And-1’s.”

Like most good defensive techniques, the key for Pierce is doing the dirty work before James gets the ball.  

“I can do a good job of eliminating his speed just by limiting his catches,” Pierce said. “Keeping the ball out of his hands in transition, and as a team load up on him so we can take his speed away. But it’s all about how strong he is he once gets into the paint. We have to do a better job of not letting him get the ball to the rim where his strength comes into play where he’s finishing with And-1’s and dunks.” 

And if he does get a head of steam heading to the basket? 

“He’s tough to stop,” Pierce said. “He’s either going to get fouled or he’s going to get the shot up. You talk about a runaway train going full speed going right at the rim, a guy 6-8, 250 pounds pushing the ball full speed, it’s tough to guard. Especially with his footwork, change of direction, the way he’s able to get the angle, that’s why he gets to the line so much.” 

Pierce will have to avoid foul trouble, especially because the Celtics will need him on the floor for his offense. Ray Allen faced a similar issue with Wade, and except for a few minutes in Game 5, he was able to stay in the game and contribute offensively. 

“It’s a tough one, but Ray just had it,” Rivers said. “Ray proved that you could do both. Ray shot the ball well and he had to guard Wade a lot. We do have extra guys because we have Tony [Allen] and Paul. We have Ray and we have Marquis in this series. I just want [Pierce] to be what he is. I don’t expect less out of him.” 

Part of what makes James so good is his willingness and his ability to pass the ball over the top of defenses. 

“He’s a bullet passer,” Rivers said. “He’s the only guy that I know of like Magic [Johnson]. The steam, bullet passes. He throws cross-court passes that go a hundred miles an hour. It’s tough to react. If you’re standing straight-up on the weakside, there’s no way you can get out to that shooter. He’s a great passer.” 

The Celtics want to get the ball out LeBron’s hands, but here’s what they have to deal with when they succeed. 

DEFENDING THE 3-POINT LINE 

The Cavs shot 38 percent from 3-point range during the regular season, second only to Phoenix, and they have a number of high-percentage shooters who utilize the 3 within the flow of the offense. 

Mo Williams shot 43 percent. Anthony Parker shot over 41 percent. Delonte West had a down year shooting 3’s, but he made 40 percent last season. There’s also Daniel Gibson who may be the best pure shooter the Cavs have, but he has fallen way out of the rotation. 

“It’s not just Mo,” Rivers said. “It’s all of them. We’ve got to guard the 3-point line. If we don’t and they’re making them, then we’re in trouble.” 

James actually took more 3’s than anyone else on the Cav roster and he made just 33 percent of them. He took 27 of them against the Celtics this season, which was more than he took against any other team, but he is perfectly capable of getting hot, as he did in their first round series against the Bulls. 

The Celtics have defended the arc well this season. They ranked fourth in the NBA in opponents 3-point percentage at 34 percent. They number rose to 37 percent against the Heat, but part of that was Wade’s uncanny shooting exhibition in Game 5. 

Against Cleveland, that number has to return to their regular season level. 

THE BIG HEADACHES

Shaquille O’Neal was the big offseason acquisition for the Cavaliers, but it was their in-season move that has made them so confounding to plan against. When they traded for Antawn Jamison, they not only added the one thing they lacked – the so-called Stretch 4 – they also gave up nothing in return to acquire his services. 

After a 30-day sabbatical, Zydrunas Ilgauskus returned to Cleveland and what’s scary is the Cavs didn’t even need him in their first round series. With Jamison on board, the Cavs can play big, small or something in between, and they have a player who can step out and make jump shots. 

“He’s big for them because he stretches the floor,” Rivers said. “It gives you a headache when you think about all the different lineups that they can actually use. They and the Lakers are the most versatile teams when you think as far as all the different lineups that they can put on the floor. They can use Jamison at 3, Jamison at 4, go small, go big, Jamario Moon at 4, LeBron at 4. They have a lot of players. They go from small to big during the games quite a lot and that’s tough.”

Which one concerns him the most? 

“The ones where they have all the shooting on the floor,” Rivers said. “If we’re not scoring back, then that’s a concern.” 

The Celtics can’t match the Cavs big men in raw numbers, but in Glen Davis and Rasheed Wallace they have more depth than last season.  

“We’ve got to be able to match up with them and I think we [can],” Kendrick Perkins said. “Guys can match up with them, we’ve just got to come ready to play. I think Baby and Rasheed are going to be huge for us.” 

The Celtics are counting on Davis to equal Anderson Varejao’s energy, but Wallace will be asked to play O’Neal and Ilgauskus, who are obviously completely different players. The Celtics say they are expecting big things from Wallace. If he has anything left in the tank, now is the time to show it. 

“Our bench has to play well,” Rivers said. “It doesn’t have to be all of them. The combination of Baby and Rasheed, we need one of them, and we would prefer two. They have to play well.” 

The other component in all this is Kevin Garnett and he may be the defensive key to the series. He’ll open up on Jamison, which could take Garnett out of the paint and away from the help when James penetrates. He’ll also have to contend with the young legs of Varejao and J.J. Hickson and the Celtics can’t afford to get beat on weakside rebounding. 

With all that it still comes down to trying to contain the most disruptive offensive force in the game. 

“We’ve got to make [James] play in a crowd, but at the same time take everybody else out of the game because he makes a lot of people better,” Perkins said. “It’s a difficult task, but in order for us to advance we’ve got to get the job done.”