When the acquisition of Tristan Thompson became official, Bulls coach Billy Donovan floated the possibility of Thompson sharing the floor with center Nikola Vučević.

Our first look at the Vučević-Thompson pairing arrived in the closing stages of the Bulls’ road loss to the Atlanta Hawks on Thursday.

One night later, this time in a 118-112 home loss to the Milwaukee Bucks, Donovan chose to pair Thompson and Vučević from the opening tip.

In an attempt to foil the size and physicality of Bucks superstar Giannis Antetokounmpo, deploying Thompson at power forward was likely a matchup dependent-decision — a continuation of Donovan’s thought experiment when he surprisingly boosted two-way big man Tyler Cook into the starting lineup against the Bucks earlier this season.

Though the sample may be small, Vucevic and Thompson are a minus-16 when sharing the court together. That matches the eye test, but more importantly, it changes the Bulls entire identity for the worse.

What does this lineup mean for Vučević?

It’s early, so perhaps this changes as the experiment evolves. But based on what we’ve seen to date, if Nikola Vučević isn’t involved in ball-screen action, he’ll be wandering aimlessly along the 3-point line, acting as a deep catch-and-shoot option.

In many of the possessions highlighted within the above clip package, Vučević found himself camping out in the weakside corner. For several reasons, this is not a favorable outcome:

• The greatest utility Vučević arguably provides within the Bulls offense is his pristine passing from the post and elbow areas. If the center is removed from ball screen action and is forced to hide out in the corner, his opportunity to influence games as a playmaker will be diminished.

• Through 64 games, Vučević has largely been wayward from the 3-point line. More recently, since Feb. 1, the Bulls center has only finished 14 of his last 62 attempts (22.6 percent) from three. By having Thompson operate with the paint, thus forcing Vučević to act as a ‘spacing’ option on the perimeter, it will ultimately trigger Vučević into more looks from three. Perhaps he repairs his broken jump shot. Until then, though, Vučević is going to be forced into more attempts that haven’t been working all season.

• Since the turn of the new year, Vučević had largely erased his early-season slump, posting an average of 19.7 points, 11.6 rebounds and 3.5 assists in 34.3 minutes. Part of Vučević’s resurgence has come from making plays closer to the basket. After finally rebuilding his shot profile — and confidence — within the offensive hierarchy, is pausing this approach a solid plan in order to facilitate Thompson into the offense?

Perhaps this partnership will be more pliable if Vučević can rediscover his outside touch. Until then, he remains a shooter only in theory. 

Double-big lineups are an identity crisis

The Bulls have struggled mightily against some of the bigger frontlines the league has to offer. The worst of this shortcoming was on display in last week’s close loss to the Memphis Grizzlies. Steven Adams and Co. seemingly bodied the Bulls into oblivion any time the ball ricocheted off the basket.

If the point of the two-big lineup is to corral rebounds, it’s not working. Currently eighth overall in defensive rebounding percentage (73.6 percent), when both Vučević and Thompson share the court, the Bulls are defensive rebounding rate drops to 61.9 percent — nearly 10 points lower than league’s worst rebounding team!

No one is denying the Bulls could benefit from unleashing bigger, brawnier bodies within their rotation. However, there’s a balance to be had here. We need to remember this: The team’s entire identity on defense is built on athleticism, manic rotation, and constant activity.

Perhaps this notion has lost some momentum given the absences of Lonzo Ball and Alex Caruso. Without their defensive mavens, the Bulls have been one of the worst defenses in the league, ranking No. 25 in defensive rating since Jan. 1.

It’s been some time since the Bulls have been able to implement their primary defensive scheme, one which is predicated on forcing turnovers and fueling easy scores in transition. Occasionally, though, we’ll catch a rare glimpse of what was.

Coby White isn’t Caruso, and Zach LaVine doesn’t possess the transition passing chops which Ball has in spades. But in the above defensive sequence, they borrowed those traits from their ailing teammates.

And there was Derrick Jones Jr., in place of Thompson at power forward, gliding down the floor for an and-one finish.

This is who the Bulls are, a team who has built an identity of using their lack of size as a weapon. There’s no catching Jones Jr. and his slight frame in transition. It’s over. A willingness to go away from conventional lineups by using wing-sized players at the four spot fuels these scoring opportunities.

As they proved through the first 33 games of the season, a time when the Bulls boasted a top-10 defense, their lack of size was an advantage.

You miss out on these types of possessions when pursuing the path of playing two traditionally-sized bigs within a five-man rotation. And given the supposed benefits of being bigger have yet to materialize when Vučević and Thompson have paired together, there’s no tangible benefit with toiling through this experiment if it means sacrificing a proven defensive identity.

Who is the center?

Defining a player by position in the modern NBA can be an elementary task.

In some ways, it can also be subjective.

For example, is Vučević no longer the team’s center when paired with Thompson because he is more likely to find himself further away from the basket, facing up for jumpers?

Does Thompson’s closer proximity to the rim ultimately mean he is the true five-man?

What if one is used more as an on-ball screen option than the other? Is said player now the actual center within a specific offensive sequence?

All valid questions. But does the answer matter?

Yes and no.

Who the box score defines as the center means little. How opponents choose to guard these bigs is significant.

Let’s review what the Bucks implemented against the Bulls: the floor-spacing big (Vučević) was covered by the most athletic forward (Antetokounmpo), while also keeping their paint defender (Bobby Portis) matched up against the big roaming along the baseline (Thompson).

That methodology would hold true throughout the game.

In lineups when Vučević found himself closer to the basket — often when paired with Jones Jr. or Javonte Green — his direct opponent would shift to Portis or Serge Ibaka. Antetokounmpo would then slide over to guard the Bulls’ smaller power forward options.

It may be subtle, but this change in matchup is notable. In the first example, that which Vučević is being guarded by Antetokounmpo, it presents the Bulls with a potential issue: crossmatching defensive assignments when the offense quickly swings to defense.

The following possession perfectly illustrates this dynamic.

Attempting to body a behemoth like Antetokounmpo on the block is probably a bad idea considering Vučević is only scoring 0.85 points per possession on post-ups this season. Beyond the inefficiency of this play type, there’s also an inherent risk in this matchup for the Bulls, particularly if the play ends in a turnover, as the above possession did.

Now forced to guard in space, with little time to scramble and find the preferred matchup (Portis), Vučević has no option but to guard Antetokounmpo. Not ideal considering Thompson entered the starting lineup to defend the Bucks’ superstar.

When on the floor, Thompson is always going to be guarded by an opposing big man who likes to sit in the paint. By extension, Vučević operating more so as a face-up, jump shooting power forward invites the defense to throw a wing-sized four on Vučević.

In some settings, that could result in easy post scores for Vučević against a smaller defender. In others, particularly in those sequences when the Bulls’ offense is quickly forced into transition defense, Vučević and the Bulls may be exposed on defense (see: Lauri Markkanen playing small forward for the Bulls last season).

Size for the sake of size does not make a good defense. An already floundering defense increasing its chances of problematic matchups, all for the purpose of accommodating dual big lineups, isn’t worth the trouble.