LAS VEGAS — After further discussion with team executives from around the league here, a clearer picture is emerging of why the Celtics have yet to make the major trade they so desire.

The fact that it’s so understandable from both sides of a potential transaction explains why it is difficult at best for them to execute a deal of any great magnitude.

For a team to make a star player available, it has to seek a large package in return. More important than even making the trade palatable to its fan base, it has to be assured it can have a chance at a player who can equal the value of the key piece it is sending out. In a league where four quarters do not equal a dollar, where quantity does not make up for quality, this is imperative.

For example, even though Paul Pierce and Kevin Garnett were clearly heading for the end of their careers, they could still produce, so Danny Ainge held out with Brooklyn for three first-round draft picks and the ability to swap first-round positions in another year.

To give up a key player, a team is essentially saying it’s taking a deeper rebuilding route.

Chicago was looking at that option when it held serious talks with the Celts prior to the draft about Jimmy Butler. According to agents with interest in the matter, the asking price for the 26-year-old scorer was very high, and the C’s got protective at a certain point.

The initial key for the Bulls was the third overall pick from last month’s draft and the ability to select Providence guard Kris Dunn. The aforementioned sources added that the Celtics were willing to add one player from their rotation when Chicago wanted a second.

“Another sticking point in that and in other deals Boston is talking about is that pick from the Nets next year,” said one of these sources. “Danny will make it available in the right situation, but he’s not going to give it up with core players, too. That’s going to be a good draft, and that’s going to be a high pick.

“Everyone’s been talking about how Danny’s trying to make a killing out here, but when it comes to certain pieces you have, I get that you have to be careful. You can give up equal assets, but you don’t want to take away your best opportunities to keep things going down the line.”

In terms of other players in which the Celts are rumored to have interest, there have still been no recent talks regarding Blake Griffin or Russell Westbrook.

The Clippers are in a win-now mode, so they would need to get immediate help to consider moving Griffin. And there are also issues with the 6-foot-10 forward for the Celts and other clubs. For one, Griffin has the ability to opt out of his contract next summer, so, as was the case in the 2007 acquisition of Garnett, there would need to be assurances that he would not exercise that option and would be willing to consider signing an extension. He will make $20,140,839 this year and $21,373,952 the following season.

But, according to one opposing team exec, there is another question with Griffin.

“I still think there’s a concern with his leg,” he said, referring to a partially torn left quad tendon that cost Griffin serious time last season and never fully healed before causing him to miss the end of the playoffs. He reportedly received a bone marrow injection following the season, which is keeping him off the U.S. Olympic team.

“We looked into him, and we’re hearing that’s a pretty serious thing,” the source continued. “I’m not saying you don’t go after him, but you’d better be really sure about that leg before you go making any big commitments.”

As noted here recently, there are contractual questions that could preclude teams from going after Westbrook. Whereas Griffin has an option for 2017-18, the Oklahoma City guard’s deal runs out and makes him an unrestricted free agent next summer.

Even with the silence on these two fronts, the Celtics are still said to be very active looking for possible deals.

“Oh, Danny definitely wants to do something,” said one rival general manager. “We’ve got nothing that really works with Boston, but I bet something happens there.”

He went on to say he believes Jahlil Okafor, reported here to be a target just before the February trade deadline, may be the best fit for a deal. The question there remains whether Philadelphia and the C’s can find the right trade components, especially after they were unable to work things out just before the draft when the 76ers, after taking Ben Simmons at No. 1 overall, were hot after the third pick and Dunn.

“I still wouldn’t be surprised if something happened there,” the GM said.

In any case, the traditional post-summer league break is shaping up as anything but a break for the Celtics and other clubs.