The Celtics’ second-unit could legitimately be just as good – if not better – than the Celtics’ starters. Below I breakdown the strengths and weaknesses of each squad.

A. Sherrod Blakely of Comcast Sports Net reported on Monday that Brad Stevens’ has already tentatively established his frontcourt rotation. According to him, it will be Tyler Zeller and David Lee starting, with Kelly Olynyk and Amir Johnson serving as the second-unit’s big men.

Even if it is yet to be confirmed that Evan Turner will reprise his role as team’s starting point-forward, we can safely assume he indeed will, considering his impact last season to the first-unit’s ball movement. There’s also no reason to believe the Celtics’ starting backcourt from last year will change either. Thus, this is what the Celtics’ starting lineup will presumably be:

PG: Marcus Smart

SG: Avery Bradey

SF: Evan Turner

PF: David Lee

C: Tyler Zeller

Meanwhile, operating off of A. Sherrod Blakely’s report, we can get a pretty accurate picture of what the Celtics’ second-unit will look like. We know that it’ll likely be Olynyk and Johnson sharing the frontcourt, with Isaiah Thomas assuming the point duties. While there’s no clear candidate for the second-unit’s off-guard spot, we can assume who’ll play at the three as we all know Danny Ainge didn’t just ink Jae Crowder to a five-year deal for him to sit on the bench. While he’ll play the majority of his minutes at the three this season – because of his versatility, he’ll probably play anywhere from the 2 to the 5 spot.

Here’s what I’m assuming the second-unit will look like:

PG: Isaiah Thomas

SG: Terry Rozier

SF: Jae Crowder

PF: Kelly Olynyk

C: Amir Johnson

* There’s really no discernible difference between PF and C in Brad Stevens’ offense, defensively, however, expect Johnson and Zeller to defend opposing teams’ best post-scorer.

Regarding the second-unit, don’t expect Terry Rozier to play more minutes than Jonas Jerebko or Jared Sullinger, seeing as Stevens will likely match-up Thomas with either Bradley or Smart to compensate for Thomas’ below-average defense (he tries hard and he’s not bad one-on-one; sadly, it’s just his height limits him). But what we’re seeing with these two rotations are two very evenly matched squads, who operate differently, yet potentially better than one another depending on the situation.

Why The Second-Unit May Be Better Than The Starters

Remembering this is basketball and not hockey, we’ll probably never see Brad Stevens sub-in five players all at once (unless it’s garbage time). Thus, the “second-unit”, or the squad that frequently closes out the first quarter and starts the second, will technically be a mix of starters and bench players alike. However, for the sake of comparison, let us pretend that Brad Stevens does use hockey substitutions and plays each unit exclusively as aforementioned.

Starting with the second-unit, we see that they’re actually superior in some regards. For instance, their shooting from behind-the-arc is vastly superior than their starting counterparts. This is illustrated by the second-unit’s superior overall three-point percentages. I aggregated the averages of each rotation’s players’ three-point percentages from last season; The Celtics’ projected second-unit shot 33.9% while the starters shot just 32.1%.

While I excluded Lee and Zeller from said averages – since the two took a combined two three-pointers – it’s worth noting that everyone in the second-unit shot over 45 threes. The second-unit having five serviceable three-point shooters on the floor at once should translate into impeccable spacing. This will give the rotation’s best post-scorer, Amir Johnson tons of space to operate inside the paint. With this unit’s arsenal of long range shooters, it’d be unwise for opponents to double-team Johnson as it’d open a teammate up at the perimeter.

While this unit may not be as deadly at pick n’ rolls as the starting unit, their superior spacing should create easy one-on-one scoring opportunities. One-on-one scoring, otherwise known as “isos”, are dependent on spacing because a player cannot go one-on-one if an opposing defender can afford to slack off their assignment to double-team a player. Since Isaiah Thomas is an elite isolation scorer, it makes sense for him to share the floor with this rotation full of floor-stretchers. His ability to score on isos made him the Celtics go-to closer during fourth quarters.

Although the modern NBA frowns upon isolation basketball, isos will forever exist because it allows fourth quarter offenses – whose constituents are presumably exhausted by then – to operate in close game situations in a way which reduces the risk of turnovers. It also allows coaches to save their timeouts considering isos’ simplicity. But Celtics fans already know how effective isos are after having the pleasure of watching legendary iso-scorer, Paul Pierce deflate numerous teams with his patented isolation buzzer-beaters. Now with Isaiah Thomas picking up where Pierce left off, we should see plenty of last minute isolations this season.

Because this unit’s capable of creating the requisite spacing required for Thomas to isolate, this second-unit may resemble Brad Stevens’ closing lineup more so than the starting unit. In addition to Thomas, Amir Johnson – Danny Ainge’s most expensive (non-bird right) free agent signing ever – will likely be a staple in the closing lineup too due to his ability to protect the paint. However, expect one starting guard, whether it be Marcus Smart or Avery Bradley (or both) to close out games as well, considering their elite defense. So the most common quintet of closers will likely be a combination of starters and second-unit players.

Why The Starters May Be Better Than The Second-Unit

The Celtics’ second-unit’s scoring will be largely built-off the improvisations of Isaiah Thomas and the rotation’s collective ability to score in transition. This is common for NBA second-units, seeing as most teams have an excellent guard/wing (Like Thomas) come off-the-bench and behave as the second-unit’s primary scorer. This perhaps explains why seven of the eight past Sixth Man Of The Year recipients were gunners off-the-bench, whose respective teams’ second-units’ offense depended on them.

The Celtics’ starters will meanwhile play at a far slower yet, more deliberate pace than the second-unit. That’s not to say they’ll play at a necessarily slow pace, but they’ll run more rehearsed offensive sets, which typically eat up more time than fast-break plays.

What we’ll see from the starting lineup is a two-pronged pick n’ roll-based offense, predicated on the pick n’ roll abilities of David Lee and Tyler Zeller. This offense will look virtually the same as last season’s offense, but with David Lee at the four instead of Brandon Bass.

While Bass is a more threatening pick n’ pop option (Bass is a career 46% shooter between 10 and 16 feet, while Lee is 42%), Lee is superior post-scorer with passing abilities akin to a guard’s. The Bradley-Lee connection should be fun to watch as Bradley will frequently use Lee or Zeller as an off-ball screener for his patented mid-range jumper. Bradley can also opt to fire a pass to Lee and Zeller once they roll to the basket as well. The real treat though, will derive from Lee’s court vision that will lead to some beautiful passes to Bradley cutting baseline.

As long as Turner’s in the lineup, Smart will primarily play off-the-ball. Even with consistent minutes, Smart was never a major part of the Celtics’ schemes last season. While he was touted as one of the more NBA-ready prospects of the 2014 draft, today his offense is still years away from reaching even an average level. His shot was, while better than we all expected, inconsistent enough to be the designated shooter in a set play. He also takes way too may three-pointers with 57% of all his field goal attempts coming from behind-the-arc. This makes him far too easy to defend against as his sheer volume of 3PA’s makes him extremely predictable.

What he already has going for him is his defense. He’s arguably already a top-10 perimeter defender in the NBA. He consistently fullcourt presses his defensive assignments and he’s an effective pick-pocket – grabbing 1.5 steals per game last season, in addition to creating easy steals for his teammates. Alongside Bradley, the Celtics’ starting backcourt could quite possibly become one of the NBA’s top-three defensive backcourts (Memphis? San Antonio? Miami? Indiana? Chicago?) despite Bradley’s below-average size.

This rotation’s frontcourt, on the other hand, is limited defensively. Zeller’s a solid defender yet, Lee’s a weak defender, literally. While Lee’s intelligent enough to effectively read opponents’ offensive schemes, he’s a poor shot-blocker who gets overpowered by bruiser fours and beat off-the-dribble by stretch fours.

Turner, meanwhile, has significantly improved on defense since his rookie season but playing alongside Smart and Bradley requires him to play out of position where he’s forced to defend opposing small forwards. His inferior-strength makes him more serviceable defending off-guards rather than forwards like Paul George or LeBron James. Bradley cannot play the point because it’s beneficial to Smart’s development for him to start him at PG (not to mention Bradley’s piss-poor ball-distributing skills). Bradley’s also far too short to play SF as well, seeing as he’s only 6’1″.

What’s left is a seemingly ill-fitting puzzle, which despite all odds, kind of fits. Their defense would drastically improve if you were to switch out Turner for Jae Crowder, but at this point, Smart hasn’t demonstrated yet that he’s capable of conducting this offense. Smart just needs to marginally improve his ball-distributing skills as Lee’s passing will partially make-up for a potential Turner bench-relegation. But Smart also needs to show that he can score off-the-dribble as well.

Both Lineups Will Be Used Depending On The Situation

Last season, we often saw Tyler Zeller start the game and play until midway through the first, and then sit out until the start of the third quarter. After that, he’d get subbed-out halfway into the third and then be used sparingly throughout the fourth quarter. Sometimes he’d even sit out the entire fourth quarter, depending on the situation. Because designated Celtics-closer Isaiah Thomas plays best alongside floor-stretching bigs, Zeller was a rare sight at the end of games (except here). In fact, on average he played less minutes per game than eight Celtics players last season – clocking in at only 21 per game.

The reason I mention this is because it illustrates how differently Brad Stevens treats starters. On most teams, starters play more than every bench player on their team. For example, when Tom Thibodeau was the coach of the Chicago Bulls, his starters would always be among the five most-played on the team and typically receive 30 minutes per game.

Brad Stevens, however, doesn’t feel obliged to treat his starters any differently than his reserves. He may use the same starting lineup night-in and night-out, but more times than not, he uses a different quintet of closers every night. I’ll be you tonight’s closers, will be different than Friday’s (and that’s not just because of the players missing tonight’s game).

The second-unit may be more effective one night, while the starters are more effective the next night. While the Celtics are still without a defined star (which they desperately need), they could legitimately win 50 games this season because they have a roster of wildly-unique, albeit average, players who, if configured properly, can match-up to any team.

The starters on one hand hand, may be best against a team lacking strong post-defenders. This is because Stevens’ schemes for this unit are primarily designed to create high-percentage interior baskets by forcing the opposing teams’ bigs to make mistakes through pick n’ rolls. The second-unit, meanwhile, would tear apart any fast-paced team lacking height, since they have the speed to match-up against small-ball teams, but with the height to create mismatches.

Even slower teams with more traditional systems like the Memphis Grizzlies, will struggle against this second-unit, as their extremely reliant on their starting frontcourt, Marc Gasol and Zach Randolph, who cannot consistently defend the perimeter for 30+ minutes. The Grizzlies were also one of the poorest defenders against the three last season (allowed 10th most 3PAs and opponents shot 13th best percentage from three), despite being an elite defense.

But Stevens’ best adjustment this upcoming season will likely come when he deploys a lineup comprised of both starters and reserves. For college basketball fans, think of the Celtics as last season’s Kentucky team (minus the stars), since their depth allowed their starters and second-unit to run different sets. This confused the hell out of opponents as it was like playing two totally different teams.

But without a star, the Celtics’ puzzle cannot be completed. Yet, depending on the situation and if the pieces are expertly arranged, the team will, in a way, appear perfectly complete.

We are all very lucky to have Brad Stevens working on this ill-fitting puzzle.