The NBA league office has informed teams that they are not permitted to scout practices involving projected 2020 top-10 draft picks LaMelo Ball and RJ Hampton this season, a source told ESPN.

Representatives from NBA teams were expected to attend five New Zealand Breakers practices in Memphis and Oklahoma City this week as part of the National Basketball League team's trip to the United States for preseason games against the Grizzlies and Thunder. Teams were informed Sunday afternoon that NBA scouts are not allowed to be present to watch Hampton and the Breakers practice, a source said, though the league may discuss further clarification Monday, as no final decision has been made regarding the rest of the season.

A Sunday evening practice was closed to NBA teams that had traveled to Memphis with the intent of scouting Hampton in practice.

Ball plays for the Illawarra Hawks in the NBL, the top pro league in Australia and New Zealand. Ball and Hampton both are from the U.S.

Seventy NBA representatives have RSVP'd to attend the pro day for projected No. 1 pick James Wiseman and the Memphis Tigers on Monday afternoon, according to the team's Twitter account. The expectation around the league is that most, if not all, of those scouts will continue on to the Grizzlies' practice facility immediately after to attend Breakers practice, if permitted.

The ban stems from an interpretation of the NBA's no-contact rules, which prohibit teams from having contact with draft-ineligible players outside of a handful of approved settings, such as official games (including the Breakers' matchups this week against OKC and Memphis), select college practices and international practices involving only international players. Ball and Hampton are currently considered draft-ineligible since they have not yet officially declared for the 2020 draft through the league office.

Hampton and Ball also are not considered international players under current NBA rules, as they did not maintain a permanent residence outside of the U.S. for at least the three years prior to the draft. Therefore, practices for teams like the Breakers and Hawks that have a mixture of draft-ineligible players and players who have already been through the draft process are currently off limits to NBA scouts, based on the league office's current rule interpretation. However, 27 NBA scouts were in attendance at the NBL Blitz in Hobart, Tasmania, in September, and many of them were present at practices for both Hampton and Ball. That may result in a fine, according to the letter of the rule, depending on the NBA's final interpretation.

The NBA's no-contact rules were last updated in June 2017, and Ball and Hampton appear to be caught in a gray area. The rules might need updating or reinterpretation now that alternative paths to the NBA draft are becoming more popular with players such as Ball, Hampton, Mitchell Robinson and Anfernee Simons, who all decided to forgo the NCAA one-and-done route. The most recent 20-page no-contact memo features the word "college" 57 times and references international players 12 times, but situations like Ball and Hampton's in the NBL are not specifically addressed. The memo does have an exception for contact with players in the NBA G League.

In the past, if NBA teams wanted to scout practices featuring American prospects playing internationally -- such as Brandon Jennings, Emmanuel Mudiay, Terrance Ferguson and Brian Bowen -- they would simply travel overseas and attend without consulting the league office. Since the Breakers' tour of the U.S. presented all 30 teams with the unique opportunity to evaluate Hampton in an NBA arena, this matter was put under the spotlight and brought to the league's attention in a more visible way.

Hampton, Ball and NBA teams wishing to scout their practices have a case to argue that the two are already draft-eligible for 2020. When the NBA releases the early-entry list for prospects who have elected to make themselves eligible for the draft, Ball's and Hampton's names will be included, whether or not they send a letter to the league office prior to the early-entry deadline. That is because they signed professional basketball contracts with teams in leagues other than the NBA prior to Jan. 1, 2020, making them "also eligible" for selection in the 2020 draft, according to league rules.