The Jim Boylen era in Chicago has gotten off to a decidedly rocky start. Within a week of being named the Bulls' new head coach, Boylen’s attempt to put his players through a tough practice after a record-setting loss reportedly resulted in some of them complaining to the National Basketball Players Association.

Yahoo Sports first broke the news Monday, with the website’s Vincent Goodwill and Chris Haynes reporting that the Bulls players felt Boylen was employing “extreme tactics.”

According to Darnell Mayberry of The Athletic, the “tipping point” came after the 56-point home loss Saturday to the Celtics, which was the second of a back-to-back set for Chicago, with Boylen’s intention of holding a “grueling” session on Sunday pushing the Bulls to the “brink of a full-blown mutiny.”

After taking over from the fired Fred Hoiberg on Dec. 3, Boylen had already put the team through several lengthy practices that, according to Yahoo Sports, included “extra wind sprints and players doing military-style pushups.” Holding a practice after two straight games, though, is generally regarded in the NBA as a no-no, and some Bulls were also upset that, during the loss to Boston, Boylen had twice pulled all five players off the court at once for mass substitutions, including less than three minutes into the third quarter.

“My job is to try to push our guys to a place they can’t take themselves,” Boylen, who was an assistant to Hoiberg and often played the “bad cop” role, said Monday (via the Chicago Tribune). “That’s pushing them outside their comfort zone. That’s what the [team owner] Reinsdorfs are paying me for.”

According to multiple reports, Bulls players exchanged group text messages as they considered boycotting the Sunday practice altogether. They ultimately decided to show up at the team facility but eschew the planned session in favor of discussing their grievances, both among themselves and also in a meeting with coaches.

“The main thing that we can tell you guys is that we went in there and we went in as a unit,” Chicago’s Zach LaVine, who had complained about “the players’ toughness” being “questioned,” told The Athletic. “I think we needed to get a lot of stuff off our chest and be transparent. I think moving forward that will help us.”

Of the players' complaint to their union, Boylen said Monday that they had “every right to do that” and that he wasn’t “taking it personally.” He asserted that his team did not “splinter” after the loss to Boston, which left it with a 6-21 record heading into a home game Monday evening against the Sacramento Kings.

“There was an issue with how we’re going to go about things with practice, what I value and that they have to understand this is not a negotiation,” Boylen said. “That’s not my style. That’s new for them. And that’s okay.”

The Chicago Sun-Times reported Monday that the Bulls' front office had been unaware of the Yahoo Sports report about the complaint. Team executives did describe Boylen’s job security as “safe” and told the newspaper, “Jim handled [Sunday] really well. It was a teachable moment for our young guys.”

“The truth is, we had a couple guys who thought a Sunday practice was excessive after the week we had,” Boylen said (via the Tribune). “And they have to trust me that if I bring them in here to practice, I’m going to manage their legs and manage what we’re going to do. They didn’t understand that. So I explained to them, ‘You have to trust that I’m going to do what’s best for this team.’ What was best for this team was coming in, being together and growing. Some guys felt that was excessive.

“We cleared that up, and we’re moving on. . . . Everybody is allowed to make a mistake. Everybody is allowed to get sideways a little bit.

“This is an emotional roller coaster at this level,” Boylen continued. “New coach, tough week, big win, got our butt kicked. Everybody is human, has a reason to do what they do. We’ve all done it, where we look back and say, ‘God, I wish I would have done that differently.’ We could have handled that differently. Okay. Is that clear?”

Read more from The Post: