LAS VEGAS -- Commissioner Adam Silver said multiple times during his annual news conference in Las Vegas during summer league that the NBA has "work to do" when it comes to free agency and the rules governing it.

Silver's comments came after a free-agency period in which several star players changed teams through deals that were apparently agreed upon before the official start of free agency at 6 p.m. ET on June 30.

"My sense in the room today was, especially when it comes to free agency and the rules around it, that we've got work to do," Silver said Tuesday evening at the conclusion of the league's annual board of governors meetings. "And as I said, it's still the same principles of fair balance of power and a sense that it's a level playing field. I think that's what teams want to know. I think they're put in difficult situations because when they're sitting across from a player and whether it's conversations that are happening earlier than they should or frankly things are being discussed that don't fall squarely within the collective bargaining agreement, it puts teams in a very difficult position because they are reading or hearing that other teams are doing other things to compete, and at the end of the day, that's what this league is about: competing for championships.

"My job is to enforce a fair set of rules for all our teams and a set of rules that are clear and make sense for everyone. I think right now we're not quite there."

Silver acknowledged that there always have been at least some discussions taking place before the official start of free agency. This year's free-agency period, though, put into stark relief just how much of that business is done ahead of time, with basically only Kawhi Leonard's search for a new team lingering past the first 24 hours in which players could agree to contracts with teams.

The league has only so many ways it can police tampering, particularly when it comes in the form of players talking to one another, something the NBA has no realistic way to combat. And while Silver wasn't directly addressing that topic during his news conference Tuesday, he did repeatedly say that he believes the league needs to look at having "enforceable rules" on its books.

"I think the consensus at both our committee meetings and the board meeting was that we need to revisit and reset those rules, that some of the rules we have in place may not make sense," Silver said. "I think that's what we discussed. I think it's pointless at the end of the day to have rules that we can't enforce. I think it hurts the perception of integrity around the league if people say, 'Well, you have that rule and it's obvious that teams aren't fully complying, so why do you have it?'

"I think the sense in the room was we should revisit those rules, think about what does make sense for our teams so that ultimately we can create a level playing field among the teams and that the partner teams have confidence that their competitors are adhering to the same set of rules they are."

All of the player movement this summer -- coupled with the star players available almost all choosing to sign with teams in either California, New York or Florida -- also led to questions about whether that was a potential long-term problem for the league.

Silver said he wasn't overly concerned by it. But he added that he was cognizant of the fact all 30 teams need to feel they have a chance to compete on a level playing field.

"I think at the end of the day, it's positive for the league," Silver said. "I will say, though, I'm mindful of this notion of balance of power, and I think it applies in many different ways. An appropriate balance of power between the teams and the players, an appropriate balance of power I'd say among all our 30 teams, big markets, small markets, some markets that are perceived as being more attractive than others, tax issues, climate issues. At the end of the day, you want to make sure you have a league where every team is in a position to compete.

"We have work to do. I think some of it is systematic, can only be addressed through collective bargaining. ... I never want to say it's without concern. Certainly we watch everything that happens, but again, having had a long-term perspective in the league, I think we continue to incrementally get better."

One thing Silver said he remains unhappy with is players making public trade demands. After previously decrying the practice, Silver said it continues to be something the league has to address in the wake of Anthony Davis being sent to the Los Angeles Lakers several months after making his trade request public before February's trade deadline, and Paul George going to the LA Clippers after privately making his own trade request last week.

"First of all, you know, of course that's nothing new in the league in terms of trade demands. But it concerns all of us," he said. "I mean, it falls in the same category of issues of the so-called rule of law within a sports league. You have a contract and it needs to be meaningful on both sides. On one hand, there's an expectation if you have a contract and it's guaranteed that the team is going to meet the terms of the contract, and the expectation on the other side is the player is going to meet the terms of the contract.

"I will say, without getting into any specific circumstances, trade demands are disheartening. They're disheartening to the team. They're disheartening to the community and don't serve the player well. The players care about their reputations just as much. And so that's an issue that needs to be addressed."

Silver was also asked about the decline in TV ratings this season, which he said could be attributed to several things, including cord cutting and pirating, but said he wasn't concerned about it overall.

Silver did, however, say that the way the media landscape has changed since the league's current television deal was agreed to five years ago could lead to the NBA attempting to reopen it with its television partners -- ESPN and Turner Sports -- to allow the league to better optimize its business.

"It's amazing to me, again, having been at the league for a long time and having watched change over the years, how much that change is now accelerating," Silver said. "I think even just from the time we negotiated this set of television deals less than five years ago. I think there's a realization with us with our television partners that at the end of the day, even though we have six years left on these deals, there are potentially modifications we should be making so we can do a better job finding those fans.

"So I don't think there's anything endemic to the league. In fact, at our board meeting we discussed the growth in popularity of the sport, the growth in participation, the fact that we have a young, diverse, global audience. All very positive indicators. But at the end of the day, a large component of our revenue come from traditional media. It's not something we can ignore and it's something that we and our television partners need to address."

Silver also added he isn't concerned about the number of rookies either sitting out of summer league completely or being shut down early like No. 1 overall pick Zion Williamson, calling it "unique circumstances."