Closing time for these series?

Three first-round series have a Game 6 on Thursday, as the Bulls visit the Sixers, the Celtics host the Hawks and the Lakers play the Nuggets in Denver. Can the Bulls, Hawks and Nuggets extend their series or will the Sixers, C's and Lakers move on the next round? Our roundtable debates.

1. What should we watch most closely in Hawks-Celtics Game 6?

Henry Abbott, TrueHoop: Healthy and together, Josh Smith and Al Horford are killing the Celtics on the boards. In Game 5, Kevin Garnett got 12 percent of available rebounds. Smith got 22 percent and Horford 17. I expect Boston to win, but it's not clear how the Celtics can solve that particular riddle.

Zach Harper, Daily Dime Live: Joe Johnson vs. Paul Pierce. I know this sounds like a huge mismatch and, well, maybe it is. Despite his ginormous contract, Johnson's on-court value has been really high this season. The Hawks need him to match probably 80 percent of what Pierce does to have a chance to win in Boston.

Beckley Mason, ESPN.com: Who looks more energetic: Horford or Pierce. Both players are battling injury and fatigue. In Game 4, Horford played 41 minutes and had 11 rebounds in his second game after a four-month layoff. Pierce couldn't even hobble to free throw line once. Whichever team has the more active star wins.

Rob Peterson, ESPN.com: Horford's energy level. In Game 5, Horford not only provided muscle (11 boards) and points in the paint (19), he also provided inspiration. But he also provided perspiration, playing 41 minutes, the third-most minutes he's played all season. He may have been able to keep his legs in shape during his rehab after pectoral muscle surgery, but players will tell you practice shape is different than being in game shape. I'm wondering if Horford will have the same bounce in Game 6.

Michael Wallace, ESPN.com: Horford's impact. If Horford duplicates his Game 5 effort, when he had 19 points, 11 rebounds, three steals and three blocks in his second game back from chest surgery, this series could very well swing in Atlanta's favor. But you know how it is with the Hawks. Just when you expect one thing from them, they deliver another.

2. What should we watch most closely in Bulls-Sixers Game 6?

Abbott: The Bulls' mood. They went into a low-energy funk after Derrick Rose's injury. But in Game 5, just like every game of the past two seasons, they played hard, screamed loud and knocked people around. THAT Bulls team has a chance in the series, if it shows up.

Harper: Do we have to watch this? Let's just make it simple and say it's a points watch. Lawler's Law is first to 100 wins the game. This one is going to be really ugly. How about we make George Mikan's Law? First to 70 points wins this game.

Mason: Who is getting the cheap points? If the first five games are any indication, this game is going to be an ugly mess. Whether Chicago can pick up a few points off offensive rebounds and how Philadelphia capitalizes on transition opportunities will be vital to the final result.

Peterson: Joakim Noah's health. If Noah can return from his sprained ankle, what kind of lift would that give the Bulls? He averaged 15 points and a shade more than nine boards in the three games he played. Those numbers could help the Bulls avoid this ugly one: five, as in being the fifth No. 1 seed to get the bum's rush by an eighth seed.

Wallace: Noah's left ankle. The Bulls' energetic and eclectic center is a "game-time decision" for Game 6 after missing the previous two games against the Sixers. If Noah can go, then the Bulls have a legitimate chance to extend this series to Game 7 in Chicago. If not, the Bulls likely won't have much of a leg to stand on.

3. What should we watch most closely in Lakers-Nuggets Game 6?

Abbott: The Nuggets' candidacy here was always rooted in youth and athleticism. If that was ever going to work, this is the time. The breaks between games are short. The altitude is high. The Lakers' big three each played 37-plus minutes in Game 5. Meanwhile, young JaVale McGee is feeling empowered, while the athletes with the seriously intense motors, Kenneth "Manimal" Faried and Corey Brewer, are fresh after playing short minutes.

Harper: The obvious answer is McGee but I already know you won't be able to take your eyes off him. How about the tempo of the game when Denver goes with the Lawson-Miller backcourt? If the Lakers can keep the game slow in those stretches, they'll close out this series. If not, Denver will run all night to victory.

Mason: Watch the Nuggets' big men run. This is the whole series, really. In Game 5, McGee and Faried sprinted past the Lakers' plodding front line. You should also watch for it because you don't want to miss any fast-break lobs!

Peterson: Andrew Bynum's focus. When Bynum's on, the Nuggets don't have anyone to stop him. But when he talked about how easy close-out games were, Bynum provided bulletin board fodder for a desperate team. We can debate about how much that inspired Denver as opposed to the prospect of the Nuggets' desperately trying to fend off the offseason, but if the Lakers want to take care of business in six games, Bynum has to be all business in Game 6.

Wallace: Will the Lakers make Bynum a major priority? The Nuggets have obviously geared their defense more toward slowing Bynum since he got that triple-double in Game 1. Throwing as many as five different defenders at Bynum has affected his rhythm a bit, yet he's still shooting better than 60 percent in the series on just under 12 shot attempts per game. Kobe Bryant needs to donate about six of his attempts to Bynum in Game 6.

4. Fact or Fiction: The Celtics and Sixers will meet in the next round.

Abbott: Fiction, but only because John Hollinger scrambled my brain into believing it's likely some team or another that was once down 3-1 is likely to win. The Bulls and Hawks are, for various reasons, good candidates -- they both have home-court advantage. And in the case of the Hawks, they are -- with Horford -- a much better team than they appear in the standings.

Harper: Fact. Hard to imagine Chicago overcoming these injuries to win three straight games. It's also hard to imagine the Hawks coming through at any moment in a playoff setting. I don't trust Atlanta to be successful here.

Mason: Fact! And when they do, I also think the Sixers will give the Celtics real problems. Pierce isn't going to light up Andre Iguodala, and Pierce will have trouble chasing him down in the open court. The Sixers' stifling defense and team quickness give them a real chance to get to the Eastern Conference finals.

Peterson: Fiction. I think the Celtics and their burnished playoff mettle close out the Hawks in six, while the Bulls, fortified by Noah's return and Tom Thibodeau's grind-it-out game plan on both ends of the floor, take Game 6 in Philly and Game 7 and at home.

Wallace: I'm not saying that Celtics-Sixers won't happen in the second round. I'm just not ready to declare it a flat-out fact just yet. If Horford and Noah can give their teams anything, they've got a chance. Despite being down 3-2, it's not out of the question that the Hawks and Bulls can force Game 7s on their respective home courts. And from there, anything's possible. So yes, it's way too soon to declare any facts right now.

5. Fact or Fiction: The Lakers and Thunder will meet in the next round.

Abbott: Exciting though the Nuggets are to watch, and real though I think their chances are, I'm sticking with my Lakers pick. I could see the Nuggets making some magic in Denver, but with Game 7 in L.A., and the weight of championship experience on their side, it's hard to see the Lakers losing this.

Harper: Fact. As much as I want to see Denver continue to play, can we really ask them to win three straight games (including two on the road) against a bigger and better Lakers team? At some point, the Lakers should get the Nuggets to break and move on to OKC.

Mason: Fact. I think it will take seven games, but I have faith that the Lakers will find a way to get a good game out of Pau Gasol, Bynum and Kobe on the same night. But come Round 2, the Thunder's unrelenting waves of speed and skill will overwhelm the Lakers in five, maybe six games.

Peterson: Fact. As much as I love George Karl and as much as the Nuggets are a fun team to watch, I think the Lakers squeak out a win in Game 6 and advance to meet the Thunder, who will then take that series in six games.

Wallace: Fact. The Nuggets have fought a valiant fight. But it's time the Lakers show that they're seriously a title contender, exploit what should be their matchup advantages inside and put this series away. There have been too many stretches of lazy and lethargic play already. The Thunder have already taken care of business. The Lakers will do the same Thursday night and set the stage for what might prove to be the best series of the postseason, including the Finals.

ESPN.com and the TrueHoop Network
Henry Abbott writes for TrueHoop, Zach Harper hosts Daily Dime Live and Beckley Mason writes for ESPN.com and contributes to the True Hoop network. Mike Wallace writes for on ESPN.com and Rob Peterson is an editor for ESPN.com.
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