CHICAGO — The Knicks were at full strength Friday night. Well, let’s say they had their complete roster available.

Mitchell Robinson was back, making his season debut. Deuce McBride returned to the team. All of the banged-up players on the injury report were a go. And the Knicks still looked to be the work in progress that they have admitted they are right now as they were knocked off by the Chicago Bulls, 135-125, at the United Center, suffering their third consecutive loss to fall to 2-3.

The Knicks seemed to be full and balanced in some ways. Four players exceeded 20 points, as Jalen Brunson had 29, OG Anunoby 26, Mikal Bridges 23 and Karl-Anthony Towns 22. But even with all of the pieces, it still did not appear to be fitting together yet.

Robinson played 21 minutes, scoring four points and pulling down 11 rebounds, and his defensive presence did little to slow down the Bulls (5-0).

The Knicks fought back from a 22-point deficit but never got all the way back. And in the end, it wasn’t Robinson who was the center that made a difference but Chicago’s Nikola Vucevic, who scored six straight points at a point when Towns was misfiring on three three-pointers in the final minutes, two of them wide open.

Vucevic then found Josh Giddey, who finished with a career-high 32 points, for a layup. The run turned the Bulls’ two-point advantage into a 12-point lead and sent the Knicks to a timeout with 1:44 remaining.

“It’s real simple tonight,” Mike Brown said. “We lacked physicality that we wanted to have and we’ve been showing on the defensive end of the floor. Our ability to guard the basketball was not good in the first half. We were getting blown by possession after possession after possession.”

“We didn’t have any game-plan discipline,” Brunson said. “We didn’t do what was asked of us. Coach came up with a game plan and it’s on us to deliver. We can’t switch the game plan if we don’t do the game plan hard enough. I don’t know what to say.”

The biggest question was when Robinson would play and just what would follow even when he got into the lineup. While he did make his return and was in the starting lineup, no one seems able to answer just how long the return will last. Will he play in back-to-back games? Will the workload management that oddly had him on the court in preseason and then sitting out the first four games of the regular season continue throughout the season?

So he was asked about that. Is it going to be like this all season?

“I don’t know,” he said.

The Knicks made big changes in the offseason, bringing in Brown as their coach to replace Tom Thibodeau. He brought with him new systems, discarding the ones that already had brought this group to the Eastern Conference finals last season. But moving Robinson into the starting lineup and putting Josh Hart on the bench might be the riskiest move of all.

If Robinson is a mystery, the Knicks knew exactly what they were getting in Hart, who did not play at all in the fourth quarter Friday. He played more minutes per game than any other player last season — not just on the Knicks but in the entire NBA. He is not a shooter like Towns or a scorer like Brunson, but he set a franchise record for triple-doubles in a single season, breaking the mark set by Walt Frazier.

Hart was as much a part of what the Knicks achieved as anyone, and he did it while Robinson sat out the first 58 games of the season and played only 17 regular-season games. In the playoffs, when Hart struggled with a broken finger and some admitted fatigue, he suggested to Thibodeau that he make a change — putting Robinson in the starting lineup and dropping him to the second unit.

We can debate the importance of a starting five; most coaches will point out that the closing five is the most important lineup. And the reasoning for putting Robinson in the starting lineup is understandable. But there also is a difference in relying on him for one night in the playoffs versus the marathon of a season.

When healthy, Robinson can make an impact with elite defensive skills and rebounding prowess. But that “when healthy” is a huge issue. Robinson sat out the first four games of the season as well as the final two preseason games, with the Knicks insisting there was no injury and that this is all part of a plan.

“It’s harder, but it’s part of the process,” Brown said. “Can it be done? Yes. Will we get it done? Yes. It’s something that we embrace because we want the best possible version of Mitch we can get.’’

The Knicks seemed ready, opening a 13-5 lead, and that was about the last time there was a positive until Bridges’ buzzer-beating three-pointer bounced high off the back of the rim and fell through. Between those moments it was an avalanche. The unbeaten Bulls scored at will, connecting on 10 of 21 three-pointers in the half and 59.5% of their shots overall in building a 72-53 halftime lead.

Robinson had little effect on the defense, often seeming to be a step slow on rotations and watching Bulls guards race past him to the rim or Vucevic drain three-point field goals from beyond his reach.

Trailing by as many as 22 in the second quarter, the Knicks rallied in the third quarter to get within 85-80 before the Bulls answered with eight straight points and took a 100-91 lead into the fourth quarter.

Steve Popper

Steve Popper covers the Knicks for Newsday. He has spent nearly three decades covering the Knicks and the NBA, along with just about every sports team in the New York metropolitan area.