Looking ahead to Boston vs. Miami: Part II

The Heat-Celtics mega-series begins Sunday at 3:30 p.m. ET on ABC (Damian Strohmeyer/SI)

The mega-series gets a two-part preview. On Thursday, we looked at some key issues that will arise when the Heat have the ball. Today we look at the matchup between Boston’s offense, which ranked below the league’s average this season in points per possession, and Miami’s top-five defense. The Celtics have been mediocre on offense for two straight seasons now, and though their defense was good enough to carry them to the Finals last year, they won’t be able to beat Miami four times if they can score at a decent rate.

Here are some of the key things to watch for when the ball is in the Celtics’ hands:

• Who will guard Rondo? 

We know teams prefer to play far off Rajon Rondo, daring him to shoot jumpers as a way to squeeze Boston’s half-court offense, but we also know some teams can pull this style of defense off better than others. Ideally, you want the guy guarding Rondo to be quick and long-armed enough to muck up passing lanes, contest his drives and help on Boston’s players moving without the ball while still being able to find Rondo.

LeBron James and Dwyane Wade are ideally suited for this assignment, and both will probably see minutes on Rondo. How often they guard him will depend in part on how the rest of Miami’s rotation shakes out, since having one of the Heat stars guard Rondo means having a non-star defend either Ray Allen or Paul Pierce.

If Mario Chalmers replaces Mike Bibby as the Heat’s starting point guard, he might be quick enough to chase Ray Allen despite giving up about four inches in height. Asking Bibby to guard Allen is asking for Allen to catch fire, and Allen’s 14-of-27 performance from deep in Boston’s first three games against Miami (all Boston wins) taught the Heat a lesson about what happens when Allen gets space.

On possessions when Bibby gets the assignment, look for Rondo to be aggressive off the dribble and even in the post.

The wild card here is Miami’s ability to go with no traditional point guard — something it’s been willing to do late in big games. When Miami plays those groups, it can have a bigger player guard Rondo without sacrificing anything on Pierce and Allen.

Regardless, the Celtics know how to attack this defense, and they know the pitfalls they must avoid when facing it. Rondo has be a willing shooter, and when he doesn’t have the ball, he must be active cutter, especially around the baseline, where he loves to lurk. Pierce and Allen will be active running around screens, and the big guys are going to have to make those screens nasty. Boston will work the Pierce/Kevin Garnett pick-and-roll and the Pierce/Rondo pick-and-roll, the latter of which is designed to draw a switch. And Garnett will need to establish himself in the post both as a scorer and as a distributor who can run the offense from there if it bogs down elsewhere.

But most of all, Boston needs to …

• Push the pace

Boston does not play at a fast pace, and it’s not going to score on fast breaks that look like Miami’s transition attacks. But the Celtics thrive when Rondo is able to push the tempo, get ahead of the field, pull up and survey the scene before Boston’s opponent has all its matchups set. Rondo is fantastic at finding big guys trailing in the lane and shoveling the ball to shooters on the perimeter. Even if that initial pass doesn’t lead directly to an open look, it keeps the defense scrambled and opens things up elsewhere.

This kind of action is especially important for a team that can struggle at times to create in the half-court. One example of that: Boston ranks about average in field-goal percentage on shots taken in the last four seconds of the shot clock, and “average” in any shooting category is pretty bad for one of the league’s very best shooting teams. That number speaks to the problem Boston has creating good looks in isolation with the clock winding down; every team suffers in that situation, but few suffer a drop in field-goal percentage as dramatic as Boston’s.

Rondo can’t play at a break-neck pace all the time — no one can — but he is capable of carrying Boston’s offense this way for a few minutes here and there. Boston will need a bunch of those stretches to score enough in this series, and it can’t afford to blow too many of them with…

• Turnovers

In the four seasons since the new Big Three came together, Boston has ranked (in chronological order) 29th, 29th, 27th and 28th in turnover rate, which measures the percentages of a team’s possessions that end in a turnover. In short, this team cannot take care of the ball, and though it tends to get a little better at it in the postseason, it’s not going to morph into the Blazers. But the Celtics have to find a happy medium, especially against a team so destructive in transition.

Miami does not force a lot of turnovers, but that reflects a philosophical choice rather than a lack of ability, and Boston is pretty generous regardless of the competition. It will have to clean up the sloppier stuff — the no-chance-in-hell outlet bombs, Rondo’s showy dribbling, the one-pass-too-many interior dishes and the occasional tendency of a couple of guys here to drive into crowds.

• Will Wade wander?

Dwyane Wade recently acknowledged his bad habit of wandering from outside shooters to pursue things elsewhere, and it’s something he absolutely has to avoid against Allen. With roster turnover that saw Rasheed Wallace, Eddie House and Nate Robinson leave, Boston went from shooting an average number of threes to barely shooting any; only the Raptors and perpetually three-phobic Grizzlies attempted fewer triples this season. That has created occasional spacing issues for Boston, and the Celtics’ offense functions much better when they hit a few extra threes to loosen things up.

Boston averages five made threes per game. When it hit at least six — just one more than their average — Boston is 25-6. When it hit seven or more, Boston is 19-1, including two of their four wins over Miami.

When Boston gets even a little space to breathe — or a couple of extra threes in transition — it’s deadly. Whoever is guarding Allen must stay home.

• Big Baby’s time

For all the hoopla over the Kendrick Perkins/Jeff Green trade, Glen “Big Baby” Davis was always going to be the fifth member of Boston’s crunch time lineup. Davis often finds the ball in his hands with the shot clock running down, since he can pop open when the defense collapses elsewhere. And he’s a nifty scorer when his game is on; he can isolate against smaller players, get to the rim and draw contact.

His mid-range jumper isn’t as accurate as he thinks it is, but it’s usable and Davis is certainly going to use it. Boston will need him to hit a higher percentage than he did in the regular season, when he was one of the very worst shooters among guys who took a lot of long two-pointers.

It’s easy to say lots of role players need to “step up.” Jeff Green has to play much better than he has since the deal, and he’s going to have chances to defend LeBron James. Delonte West has to be helpful. One of these guys might swing a key run that can in turn swing a game.  But among Boston bench players, it’s Davis that must be consistent, because it’s Davis alone among that crew that is going to play heavy minutes.

• PREDICTION: This is going to be an intense series, and it wouldn’t shock me if Miami won this thing in five games. But as I outlined on Thursday, Boston’s defense is good enough — and smart enough — to drag this series down to a place where Boston can win it. Miami’s absolute best beats Boston’s absolute best, but the Heat have not learned how to play that way for 48 minutes, and Boston’s defense can stifle anything less than Miami’s best game.  Toss in a big series from Rondo, and I’ll stick to my pre-playoff prediction: Celtics in six.