Bulls second-year center Wendell Carter Jr. underwent surgery Tuesday for what has been called a “core muscle injury,” with the hope still being he can return in time for training camp.

If not, there are options — not exactly a statement that could have been made about the Bulls in previous years.

No Carter? Put newly signed Luke Kornet into the starting lineup.

No Carter? Slide forward Lauri Markkanen over to the five and start newly signed Thaddeus Young at the four.

No Carter? Otto Porter Jr. moves to the four, Markkanen to the five and newly signed Tomas Satoransky starts alongside Zach LaVine and rookie Coby White.

This was the Bulls’ focus in free agency: to give themselves options.

Injuries happen in the NBA. But what too often cost the Bulls the last three seasons wasn’t just a lack of depth but also replacement players who had completely different styles. When Carter started in his rookie season last year, the offense was very different than when Robin Lopez started at center. Same issue when Kris Dunn was injured and Ryan Arcidiacono ran the show at point guard.

“I wanted a team that was [duplicative] and redundant so we could play the same way,” coach Jim Boylen said. “We’ve struggled the last couple years to play on a night when we had injury or illness — where we had to change our style of play before the game. I don’t want that. The good teams don’t have that. They plug in a guy.

“[Nets point guard D’Angelo] Russell was out, Spencer Dinwiddie would come in, and they’d play the same way. That’s just an example. And that’s what we wanted, and I asked the front office [if] we could strive for that kind of mentality. It’s hard to have ‘next man up’ when the next man up has to play in a different system than we had the game before. You can’t do that.”

That’s one of the reasons Dunn has fallen out of favor. He’s a player who admittedly wants to dominate the ball, but Boylen is looking to run a system where multiple players handle it. That means Dunn has to play off the ball, especially when LaVine is running the point. He has looked lost at times, and can mess up the spacing because even if he’s sitting open in the corner for a three, opposing teams don’t consider him a threat from out there. That means more backside help is needed, closing up the middle.

“I think we have a well-rounded roster,” Young told reporters Monday. “Injuries limited them a little [last year]. But going in, changing the culture, being the leader, it starts with being that mold where we’re doing something repetitively.”

And then it becomes a style of play where the Bulls can simply plug players in moving forward.

“I think in a league where there are one- and two-year contracts, you’re not going to have the kind of team we had in San Antonio,” said Boylen, who was a Spurs assistant coach from 2013 to 2015. “We’d have 14 of 15 [players] back [each season], and of those 14, seven or eight had been together for three or four years. The league is changing. So your system has to be simple. Your parts have to fit and cover each other.

“And that’s what we set out to do, and to support Lauri Markkanen and Zach LaVine, who are very good players but are still developing players, guys we think still have upside to them that needs to be supportive. Now we have to make it work.”