The memo said "employment contracts are to be respected and conduct that interferes with contractual relationships is prohibited," per ESPN's Adrian Wojnarowski on Friday.
It continued: "This principle is particularly important in today's media environment, where any actions or comments relating to potential player movement receive immediate and widespread public attention. Teams should be entitled to focus their efforts on the competition this season with the players they have under contract, without having to divert attention or resources to conduct or speculation regarding the potential destinations of those players in future seasons once their contracts expire."
Wojnarowski translated this as "Knock it off w/ Anthony Davis."
James, answering a question from a reporter, recently said it would be "amazing" to play with Davis, who is under contract for the next two seasons with the New Orleans Pelicans. The comment drew national attention in part because Davis is represented by Klutch Sports, the agency founded by James' friend Rich Paul.
NBA tampering rules do not apply to players, who are free to comment on other players around the league.
"Ask me if I'd like to play with Jimmy Butler," James told reporters following criticism of his remarks about Davis. "Say it right now. Ask me about Kyrie Irving, Giannis [Antetokounmpo]. Ask me about [Joel] Embiid, Ben Simmons. Go ahead, all of them. Luka Doncic. Ask me right now.
"Come on, guys, this is not rocket science. These are great players. Absolutely. I would love to play with a lot of great players. That is just who I am. People get caught up in bunches sometimes when they wish they could control what you say, and they can't control me, at all.
"And I play by the rules."
The NBA memo was more than likely both an attempt to wrest control of the narrative and a reminder to teams they do not have the same freedom as James.
Lakers president Magic Johnson has already been punished twice for his own violation of the league's tampering rules, most recently in June. James' comments could be seen as being at the behest of Johnson or Klutch.
ESPN's Zach Lowe wrote Thursday that executives around the league "don't know where LeBron ends and Klutch begins."
If Davis winds up in Los Angeles, the frustration will likely only continue to rise around the league. It's possible that the NBA could try to institute restrictions on what players can say about players on opposing teams, though that would undoubtedly receive resistance from the union.