Alex Caruso’s return to Bulls practice is significant

Point differential is the one statistic former Bulls coach Tom Thibodeau regularly fell back on.

He isn’t alone, either. Neither former coach Fred Hoiberg nor coach Billy Donovan is exactly a disciple of analytics, but both talked about the importance of a team’s regular-season point differential.

It’s not the be-all and end-all of determining which team will represent each conference in the NBA Finals because there are always outliers and other factors, but it does carry some weight.

The Cavaliers and Warriors each led their conference in point differential during the 2015-16 regular season on their way to the Finals. The Warriors led the West in point differential in 2016-17 and won the title, then were second in the West when they repeated the next season. Last season, the Bucks led the East in point differential en route to the championship.

That leads us to just how important guard Alex Caruso has been to the Bulls this season and why his return to practice Friday was so vital.

Caruso was a full-go at the Advocate Center. And while he said there was no target date for his return as he deals with normal ‘‘soft-tissue stuff’’ in his continuing recovery from a broken right wrist, he considered himself day-to-day.

The sooner, the better for the Bulls. There are a lot of numbers that illustrate Caruso’s impact on the team, but none is bigger than point differential.

Yes, Caruso makes the Bulls a top-five team in defensive rating — compared to a bottom-three team without him — but it’s the point differential with and without him that’s the real attention-getter.

In the 28 games Caruso has played this season, the Bulls have allowed 105.6 points per game. In the 38 games without him, they have yielded 114.8 for a 9.2-point difference.

As a team, the Bulls have a point differential of 1.5. That’s the lowest among the top six teams in the East, with the Celtics having the highest at 5.7. So the fact that Caruso provides a 9.2-point difference on defense not only shows the impact he has when he’s on the court — he leads the Bulls in plus/minus with a plus-5 — but how everyone else is lifted defensively by his presence.

The other number that carries weight is the Bulls’ 19-9 record (.679 winning percentage) with Caruso against their 21-17 record (.552) without him.

But here’s an asterisk:

Most of Caruso’s best work came in the easier part of the Bulls’ schedule. Of the 19 victories he has played in, 10 came against teams below .500 and only two against teams with a winning percentage above .600 (the Jazz and Mavericks).

Caruso played in two of the Bulls’ four losses to the 76ers, two of their three losses to the Heat and one of their two losses to the Warriors and was knocked out of the first meeting against the Bucks after a flagrant-2 foul by Grayson Allen caused the fracture to his right wrist.

So it’s not as though Caruso hasn’t factored into the Bulls’ disappointing showings against the NBA’s elite.

And while he still will be searching for an offensive rhythm once he returns to games, he’s being thrown into the fire. The Bulls have the toughest remaining schedule in the East, still playing the Cavaliers and Bucks twice and the Jazz, Suns, Heat and Celtics once apiece.

Translation: Caruso’s value is really about to be tested.

NOTE: Guard Zach LaVine didn’t practice because of soreness in his left knee. Like he does on most game days, coach Billy Donovan will meet with LaVine on Saturday to determine his availability against the Cavaliers.