It’s not often wise to overreact to one game of a seven-game series, especially when that one game was an outlier among three. But when that one game reinforced the concerns that a major injury triggered, it’s reasonable, if not necessary. After the Bulls followed up the news of Rajon Rondo’s fractured thumb with a Game 3 dud, there is no such thing as an overreaction. The consequences of the injury were on display at the United Center Friday night.

With Rondo now ruled out for the remainder of the first round, and with the knowledge of how much Chicago’s performance declined in Game 3, the Celtics, in a drastic turn, have become the favorite in the series. And everything that transpired in those momentous 12 hours on Friday alters the way the Bulls must approach their upset bid.

The rejigged approach wasn’t all that complicated in Game 3. Fred Hoiberg gave the majority of Rondo’s minutes to reserve point guards Jerian Grant and Michael Carter-Williams. When one of the two was on the court with Jimmy Butler and Dwyane Wade, he was often invisible on offense, ceding control to Butler or Wade. When either Butler or Wade was out of the game, the point guard was given a little more responsibility.

For around 10 or 11 minutes, though, Hoiberg went to a look that he didn’t show at all in Games 1 or 2: The no-point guard lineup. He paired Wade and Butler together in the backcourt alongside Paul Zipser and two bigs. In fact, the three different five-man combinations Chicago used that didn’t feature a true point guard played a grand total of nine minutes together throughout the entire regular season.

That lack of familiarity, however, does not mean Hoiberg should turn his back on the no-point guard lineups. It’s impossible to know how they’ll function over longer stretches, mostly because there isn’t much precedent with the current personnel. Wade and Butler played 124 minutes together this season without another guard on the court, per nbawowy.com, and 87 of them came with Doug McDermott at small forward. McDermott is now in Oklahoma City. But these lineups might be Chicago’s best route to two wins and an 8-over-1 upset.

The Bulls were thoroughly outplayed on Friday. Part of the gulf between the two teams was due to Boston’s hot shooting. But a lot of it was due to a stagnant Bulls offense. Everything the Bulls had success with in Games 1 and 2 tumbled into the abyss. They didn’t touch the 45 percent offensive rebounding percentage of Game 1, nor the 28 assists of Game 2. Grant and Carter-Williams combined for just three dimes, and the Bulls assisted on just 14 of their 33 made field goals. Without Rondo, the Bulls were stagnant. Without Rondo, the Bulls were, and are, a much different team.

So this is not a matter of getting back to what they did in Games 1 and 2. It’s a matter of finding a new way to win, even if it means going in the opposite direction, away from what worked in Games 1 and 2.

That new way might involve playing without a true point guard. The reasons for doing so are plentiful. On a simple level, it allows Chicago to get its best players on the floor more often — Grant and Carter-Williams are, at best, the seventh and eighth best players on the roster even without Rondo available.

On a more tactical level, the Bulls need the ball in the hands of Wade or Butler as much as possible, and need one of the two to initiate the offense on almost every possession, even if it means the offense halts to let them do their thing. Here’s what the no-point guard lineup looked like at its best, with Wade creating in the pick-and-roll:

This is what Chicago’s two stars did on Friday, regardless of whether a point guard was on the floor beside them. Rarely were Carter-Williams and Grant coming of ball screens like Rondo does, or like Wade and Butler do.

The value of a point guard goes beyond offense initiation, of course, and there are therefore downsides to not playing one. Point guards conduct fast breaks; they keep an offense in motion; they often provide more spacing than bigs; and defensively, they match up with opposing guards. But how many of those things do Grant and Carter-Williams actually do?

Neither was able to push the pace in Game 3 like Rondo had been doing so effectively. They obviously didn’t keep the offense in motion. Carter-Williams is a horrific shooter, and Grant is average from beyond the arc, but not better than Mirotic or Zipser. So if the point guard is just going to jog the ball up the court, give it up and stand on the perimeter to provide artificial floor spacing — which both Grant and Carter-Williams often did in Game 3 — why even have that point guard on the floor?

The case for significant playing time for both rests on the defensive end. Both Carter-Williams and Grant are plus defenders. They ranked fourth and fifth, respectively, in defensive real plus-minus among point guards during the regular season. The 6-foot-6 Carter-Williams in particular is effective on the ball.

And indeed, one of the routes to an upset is to stifle the Celtics and win two low-scoring games. If Boston shoots like it did Friday, there isn’t much Chicago can do, but if Boston is forced to rely on Isaiah Thomas to jumpstart its offense more often than not, Carter-Williams is the best antidote for the Celtics star. In that case, he could merit extended run.

Carter-Williams, however, is a black hole on offense, and gifts Brad Stevens an easy way to hide Thomas on defense. Thomas is the most exploitable aspect of Boston’s defense, and he’s especially exploitable with Grant and Carter-Williams on the bench. The 5-foot-7 Thomas can’t hang with Butler or Wade. Stevens could stick him on Zipser, but that’s still less than ideal. If he does, Hoiberg can deploy Zipser as the screener for Butler or Wade and put Boston in a pickle.

Plus, if the Celtics stay small while the Bulls go to a lineup whose second-shortest player is 6-foot-7, Chicago could use the offensive glass as a weapon, just as it did in Game 1. Offensive rebounding is another key to a potential upset.

No matter what Chicago does, the Celtics should be favored in every game from here on out, or at least until Game 6. With Rondo sidelined, they are clearly the better team.

But the Bulls haven’t become an afterthought quite yet. They still have the best two-way player in the series, and a future Hall of Famer who’s won more than twice as many playoff series as the entire Celtics roster combined. Chicago’s best chance is to ride those two to victory. And the best way to ride them might be to let them share ball-handling duties almost exclusively between themselves.