This series is about trust -- how much you believe the Boston Celtics have finally come together, and how much weight you place on the Milwaukee Bucks' 86-game track record of championship-level dominance.
In the macro sense, this is a Bucks cakewalk. Milwaukee won 11 more games, with a point differential double Boston's. The Bucks hold home court. They have the best player, and they can play him as many minutes as they need.
But postseason series do not play out on the macro level. They are seven games between two teams, not 82 games against 29 rivals. Boston brings advantages that could make this a much more competitive series than big-picture numbers suggest. The Celtics can win.
Malcolm Brogdon will miss at least the first two games. Who knows how he might look upon returning. He matters a lot. (So does the injured Marcus Smart, Boston's go-to defender against Khris Middleton -- who turned into Michael Jordan in last season's playoffs.)
With Sterling Brown starting in place of Brogdon, Boston will have an easier time hiding Kyrie Irving in a series in which Milwaukee might go Kyrie hunting -- treating Irving the way Irving's Cavaliers famously treated Stephen Curry. Without Brogdon, Milwaukee has one fewer quality wing for small-ball lineups featuring Giannis Antetokounmpo (or one of Ersan Ilyasova/Nikola Mirotic/D.J. Wilson, depending on your positional taste) at center -- groups Milwaukee will need more now.
They need them because of Al Horford. He has always defended Antetokounmpo well. No one can stop Antetokounmpo -- not this souped-up version with more sneering confidence, and an emerging jump shot. But Horford makes him work. He is one of the only defenders alive capable of playing off Antetokounmpo, girding himself for the coming assault, and staying in front of the likely MVP without conceding a parade of dunks.
Scoff if you like. Antetokounmpo averaged 25.7 points, 9.6 rebounds and 6.3 assists per game on 57 percent shooting against Boston in last season's first round. Horford clearly did not stop him.
But Boston has a history of outscoring Milwaukee with Horford and Antetokounmpo on the floor, and that extended into this season. (The sample size is tiny, obviously.) Something about that matchup troubles the Bucks.
Boston is probably not much worried about anyone beyond Antetokounmpo. Even without Smart, they have enough rangy wings to throw at Middleton, Eric Bledsoe, and the rest -- and to switch a lot. This series might come down to Horford and Antetokounmpo -- at both ends.
If Boston starts Horford and Aron Baynes, Horford and Antetokounmpo will be positional matches as nominal power forwards. Most coaches would keep with the Baynes-Horford duo. Boston outscored opponents by almost 20 points per 100 possessions with those two on the floor in 163 regular-season minutes, per NBA.com. They stabilized Boston's slumping defense. The Celtics just swept Indiana. Why change?
Baynes is also smart walling off the paint in transition -- a must against Antetokounmpo. He provides one more big help defender behind Horford.
But the Celtics could not score with Baynes and Horford against Indiana. Boston was minus-5 in 43 such minutes with a scoring mark -- 90 points per 100 possessions -- that looks like a typo.
Baynes also gives Brook Lopez a resting place on defense. That end of the floor will determine Boston's chances. Boston's defense is very good, but it can hold Milwaukee's offense -- third-best overall -- down only so much. Milwaukee should score at something like a league-average rate (at least). Boston's offense is the shakiest of the four units; can it hit league average against the NBA's stingiest defense?
Dragging Lopez into streams of Irving pick-and-rolls is the obvious soft spot. The Bucks prefer to have Lopez hang near the rim. That setup concedes open midrange jumpers. The guys defending Irving -- mostly Bledsoe and George Hill -- have to stay on Irving's hip:
But if the screen for Irving hits flush -- and if the Celtics set them higher on the floor, well above the 3-point arc -- Irving will walk into some open 3-pointers.
Boston can produce those shots with Baynes screening for Irving. Baynes sets cement-wall picks. But Lopez will not worry about Baynes popping for 3s; he can sell out containing Irving. Baynes will hit a few wide-open 3s. Boston can station Horford in the corner as a floor spacer, have Baynes roll to the rim, and pray he can make plays against a scrambled defense.
But more Baynes is a win for Milwaukee. Boston takes this series only by weaponizing the Irving-Horford pick-and-roll to a degree they never have -- and aiming it at Lopez.
Horford will hit enough of those open 3s to be a problem:
(Attacking Lopez early, in semi-transition, helps. Ditto for screen-the-screener actions, in which a third Celtic smashes Lopez as he lumbers from the paint.)
Flash a third defender at Horford, and he'll whip the ball to that guy's man -- setting off a chain of passes that usually ends in a good shot.
One way to (maybe) guarantee a lot of Lopez-on-Horford is to start Gordon Hayward in place of Baynes. That would restore the starting five Boston intended to use in each of the past two seasons -- a lineup that looked renewed against the Pacers.
(Boston could in theory start Semi Ojeleye, their "break in case of Giannis" deep-bench guy. That would allow them to play Horford at center while sloughing some of the Antetokounmpo assignment onto someone else -- Ojeleye. Defending Antetokounmpo is brutal work. Horford might wilt doing it 30-ish minutes per game. Ojeleye will play in this series, but starting him feels like overthinking. Play your best guys.)
Boston is going to play Horford at center a lot regardless of who starts. The Celtics can play that way and keep Horford on Antetokounmpo. That would require Hayward, Jayson Tatum or Jaylen Brown defend Brook Lopez, but that isn't a problem with Lopez mostly standing around the arc.
Boston has already gone this route some against the Bucks. Lopez could post those guys up, but Milwaukee has rarely veered from its core offense to do that. Boston would welcome any Lopez bully ball -- and adjust accordingly -- if it meant more of Lopez guarding Horford.
Boston ran about 30 Irving-Horford pick-and-rolls per 100 possessions in the first round -- about seven more than their regular-season average, per Second Spectrum. The Celtics should probably push that toward 40, and instruct both guys to jack a lot of 3s.
Lopez is nimbler than you might think after having watched Milwaukee plant him in the paint all season. He has shown occasional ability to step out on Irving, and recover to contest Horford's shot:
But Horford will digest that, unleash some mean pump-fakery, and blow by Lopez for more profitable stuff. Creeping out also exposes Lopez to Irving turning the corner into the same 5-on-3.
Boston varying its Irving-Horford attack is important. Milwaukee is probably fine with Horford shooting 10 semi-open 3s per game from above the break. The Bucks have let better shooters chuck. Few big men want to shoot over and over -- especially if they miss two or three straight. Guilt sets in. They hesitate. Hesitation kills. The Bucks also know opponents will never generate layups or free throws that way.
That's what makes this matchup so interesting: Milwaukee is hell-bent on taking away shots at the rim and free throws, but Boston is already terrible at producing either. The Celtics ranked dead last in free throw rate and 27th in the share of shots that came at the basket. Most teams lose something against Milwaukee. Boston is already playing how Milwaukee wants its opponents to play.
That should help the Celtics. They are designed to take the sorts of shots Milwaukee concedes. The trends turned even more extreme in three regular-season matchups; Boston's attempts near the basket plummeted, and the Celtics redistributed almost all of them into non-corner 3s, per Cleaning The Glass.
Almost every team needs to shoot well to beat another good team four times in seven tries. Duh. But that is especially so for Boston here. If the Celtics can manipulate rotations and schemes to produce the right jump shots, and make a lot of them, they can pull the upset.
They should get a ton of shots up, too. Milwaukee ranked 25th in forcing turnovers, and Boston takes care of the ball. In three regular-season games, Boston coughed the ball up on just 8.2 percent of its possessions -- miles below the league's best turnover rate. A total failure to get to the rim and the line doesn't hurt as much if you shoot on every trip.
Of course, Milwaukee does not have to just accept the Lopez-on-Horford matchup. The Bucks could hide Lopez on Brown or Hayward, and have Antetokounmpo chase Horford off open 3s. (When things get tight, I suspect Antetokounmpo will defend Horford more than ever.) Boston could counter by using those guys in screening actions -- shoving Lopez right back onto center stage.
Milwaukee could slice Lopez's minutes, and play Antetokounmpo more at center. Those lineups can switch a lot, and vaporize Boston's open jumpers. Horford can post up most of Milwaukee's perimeter guys on those switches. But can anyone else? Does Milwaukee fear Tatum -- Boston's best one-on-one wing -- against anyone in a Bledsoe/Middleton/Sterling Brown/Antetokounmpo/Mirotic lineup? (Side note: Mirotic could be huge in this series.)
That is one of the overarching questions in these playoffs: Is Mike Budenholzer willing to scrap the foundation that got Milwaukee this far and play an entirely different style if the situation calls for it? His playoff record does not suggest instant wholesale adaptability. Only Orlando switched screens more rarely than the Bucks, per Second Spectrum. At some point -- maybe now -- Milwaukee will need to diversify.
It's not even clear who benefits if Boston goes small and plays Lopez off the floor. It could mean Boston's small-ball lineups have devastated Milwaukee. It could mean Milwaukee has adjusted preemptively -- and removed Boston's one mismatch advantage. How do the Celtics balance playing their best lineups while keeping the Lopez/Horford matchup on the board?
But as long as Brogdon is out, moving away from Lopez could be a raw talent downgrade for the Bucks. Someone among Brown, Hill, Pat Connaughton and maybe even Tony Snell will work as the extra perimeter guy in those non-Lopez lineups. The collective performance of that group will be a swing factor.
Lopez is better than all of those guys. Any upgrade in fit might not be enough to compensate for the talent drop-off. (This is why we might see Budenholzer dabble with a super-big trio of Mirotic, Antetokounmpo and Lopez against Boston's bigger lineups -- at least while Brogdon is out. Play your best guys.)
If Boston hides Irving on defense, it will be on the Brown/Hill/Connaughton/Snell group. Maybe Boston won't hide him at all. The Celtics have not feared the Irving-Bledsoe matchup, and Bledsoe disintegrated against them last season. (Where you at, Scary Terry?) But with Milwaukee starting Brown, the option is there.
The Bucks will target Irving anyway. That is Milwaukee's easiest counter if Horford bothers Antetokounmpo's one-on-one game. The Bucks can slide Irving's guy into either side of a pick-and-roll with Antetokounmpo. Switch, and Irving is toast. Do anything else -- stay home, go under, help-and-recover -- and you'd better do it without leaving a sliver of airspace for Antetokounmpo.
(Yes, that play involves Smart. That's the point: Milwaukee should -- and probably will -- go more at Irving.)
Using Antetokounmpo as a screener is the best antidote (if Milwaukee needs one) to Horford lying in wait for his drives. It can catch Boston off guard. It triggers the rotations Boston wants to avoid. The Celtics can dip below screens when Antetokounmpo is running pick-and-roll, but not when he's the one setting picks:
The Bucks can transfer that same concept off the ball -- and direct it at Irving:
I keep coming back to this: The Bucks can play Antetokounmpo 42 (or more) of 48 minutes if they have to. He can overpower any Celtic other than Horford. Antetokounmpo has reached LeBron territory: Guys who look like they should be able to "make Antetokounmpo earn it" are really just roadkill.
Brown, Tatum, Hayward, Smart, Ojeleye and Morris each has the vague outlines of someone who "can guard" Antetokounmpo. They will all get chances. On some possessions, when circumstances are right, they will stand him up: when the Bucks get Antetokounmpo the ball too late in the shot clock, or in poor position, or when Boston can send the requisite help.
But leave any of them alone against Antetokounmpo over and over, and he's going to eat them alive. Send urgent help -- more urgent than Horford requires -- and someone is getting an open 3-pointer.
I'm also wary of declaring the mercurial, bickering Celtics have turned a corner. They scored 103.7 points per 100 possessions against Indiana -- 12th among playoff teams, and a mark that would have ranked last in the regular season. Hayward has looked bouncier and more confident, but these things don't always unfold along a continuous upward trajectory. Tatum and Brown could slump again.
Against elite defenses, you need some threshold of free throws and rim attacks to subsist. Will Boston get enough?
Every time these Celtics slumped -- every time they faced real adversity -- they teetered on the edge. It took them time to find their bearings.
They don't have time anymore. They don't have the best player, or home court in a theoretical Game 7. They have some real matchup advantages -- enough that I came close to calling Celtics in six or seven.
But in the end, I trust Milwaukee's consistent body of work more than Boston's recent good vibes and edge in postseason experience.
Bucks in seven.