NBA fans aren’t happy about players resting.

The league’s TV partners aren’t thrilled about it either.

Now, NBA Commissioner Adam Silver has once again expressed his concern about the issue in a memo delivered to teams on Monday. In the memo, he called the topic “an extremely significant issue for our league” and said teams will face “significant penalties” if they don’t follow league rules for reporting player injuries and illnesses.

One week after the Golden State Warriors sat Steph Curry, Klay Thompson, Draymond Green and Andre Iguodala against the San Antonio Spurs on a Saturday ABC game, the Cleveland Cavaliers sat LeBron James, Kyrie Irving and Kevin Love against the Los Angeles Clippers Saturday in another ABC game.

ESPN first reported the details of the memo, and USA TODAY Sports confirmed the contents of the memo.

Silver also implored owners to take an active role in managing rosters and making sure basketball operations staffer understood the business ramifications of sitting players.

On Monday, ESPN released a statement regarding teams’ decision to rest players.

"As always, our aim is to serve NBA fans with the best matchups involving the league's top stars and we share the fans' disappointment,” the statement said. “We understand this is a complex issue and we're working closely with the NBA to best address it going forward from a media partnership standpoint.”

While Cavs general manager David Griffin said the circumstances surrounding his team’s decision to sit three All-Stars was not the same as Golden State’s decision to sit four players, the Cavaliers did not follow rules for informing the league and opponents about whom may participate in a game.

As recently as All-Star weekend in New Orleans in February, Silver acknowledged it’s a complex topic.

“I do recognize, though, that there isn’t an easy solution to that problem, and I’m sympathetic to fans who turn out — whether they buy tickets to games or watching games on television and don’t see their favorite player on the floor,” he told reporters. “But we also have to be realistic that the science has gotten to the point where there is that direct correlation that we’re aware of between fatigue and injuries.

“And as tough as it is on our fans to miss one of their favorite players for a game, it’s far better than having them get injured and be out for long periods of time. So, we’re always still looking to strike that right balance.”

The league takes scheduling and health of players seriously. Over the past two seasons, it has reduced the number of back-to-backs and four-game-in-five-days scenarios and plans to start the season a week earlier in 2017-18 in an effort to cut back on those situations.

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