COVID-19 testing creates challenges for Miami Heat. And Kendrick Nunn leaves bubble.

After a month inside the NBA bubble, the league has maintained a perfect record on the most significant of scoreboards:

Not a single player has contracted COVID-19 while inside the Disney campus, after two players from other teams came to the bubble already carrying the virus.

For the Heat, COVID-19 hasn’t been an issue since Derrick Jones Jr., Bam Adebayo and Kendrick Nunn returned after testing positive for the virus in June while in Miami - something each of them subsequently disclosed. (Nunn is now out for other reasons, as detailed below.)

But that doesn’t mean there haven’t been some behind-the-scenes glitches.

According to a league source briefed by a member of the Heat’s traveling party, at least four Heat players have had some uneasy moments or been ensnared in COVID testing glitches, with the Heat and the players not at fault for any of those.

That’s hardly unprecedented inside the NBA bubble, or in any walk of life, for that matter.

Multiple Heat players have received inconclusive test results or false positives, according to the source. Those players have subsequently tested negative in each of two additional tests and were permitted to join the team for practice after those two additional tests.

ESPN cited COVID testing issues in reporting about Jimmy Butler’s absence from last Sunday’s practice. A source said Butler was blameless in that matter.

The next day, perhaps coincidentally, the NBA tightened its protocol on retesting and is now permitting players to return to the court within a 24-hour window, according to a league memo obtained by ESPN’s Adrian Wojnarowski.

Now, as ESPN reported, “a player returning an inconclusive result -- which occurs in approximately five of every 1,000 tests -- can still become eligible to play in a game that is within 24 hours -- instead of needing to wait 48 hours...

“The player must test negative in an immediate retest upon receiving the inconclusive result, and then return another negative test within 60 minutes of the scheduled tipoff of his team’s next game.”

Previously, players needed two negative tests in consecutive 24-hour periods in order to return to the court after a first test produced an inconclusive result or what was deemed to be a false positive.

The NBA is testing players daily and not a single player has tested positive for COVID-19 since teams arrived at the NBA bubble.

NUNN OUT

Heat guard Kendrick Nunn will miss Saturday’s game against Phoenix for personal reasons and has left the NBA bubble, according to multiple sources. Erik Spoelstra did not mention any issue with Nunn during a Zoom session earlier in the day.

Nunn - who previously confirmed he tested positive for COVID-19 in June - has left the bubble for reasons unrelated to COVID-19, according to a source. He’s expected back soon, according to another source, but it’s undetermined how many days he would be required to quarantine when he returns.

Length of quarantines are up to the discretion of the NBA and depend on access to testing, where a player was during his absence and other factors. Nunn is expected to have access to testing while he’s away.

New Orleans forward Zion Williamson served a four-day quarantine when he returned to the Disney camp. Clippers guard Lou Williams received a 10-day quarantine after he left to attend a funeral, but also was found to have dined at a gentleman’s club in Atlanta.

The expectation is Nunn would be back in uniform for the start of the NBA playoffs on Aug. 16 or 17 - or potentially sooner.

With Jimmy Butler out with a foot injury, Miami will be without two starters on Saturday. Goran Dragic is questionable and KZ Okpala remains out for undisclosed personal reasons. Guard Gabe Vincent (knee soreness) is probable.

Nunn has struggled with his shot in recent games, but Spoelstra reiterated his value in comments on Friday.

MILLER, ROBINSON SPEAK

▪ TNT analyst and NBA Hall of Famer Reggie Miller, one of the best shooters in league history, said he spoke to the Heat’s Duncan Robinson multiple times during the league’s suspension to share some insight and tips.

“I had a long conversation, a few of them with Duncan Robinson this summer,” Miller said.

“When everyone was locked down, he wanted to know [things]. I told him I didn’t want him to be just known as a three point shooter. He’s a great shooter but guys are going to be running him off the three point line and he needs to be able to put the ball on the court. It’s OK to be able to take a long two. You see how guys are reacting every time he catches the ball.”

Robinson said he “got connected to him through a mutual friend. He’s a guy I really look up to. He had a heck of a career doing the things that I try to do. So just to bounce some things off of him and also hear some feedback that he had for me, specifically in terms of getting open and just always being a threat -- not just being a threat from three. So I try to just pick his brain as much as possible because he’s got a wealth of basketball knowledge.”

▪ Milwaukee Bucks All-Star Giannis Antetkounmpo, on why the Heat has proved to be a formidable opponent, with Miami winning the season series 2-1:

“They move so much, set hard screens, go back door,” he said. “The ball never sticks with somebody and it’s hard to guard them. They are going to play hard every night.”

▪ Andre Iguodala entered Saturday’s game with 18 points, 15 rebounds and 12 assists over his past two games and a growing comfort level in Miami’s system.

“I’m adjusting on the fly,” he said. “There are a lot of different principles used across the NBA with different teams, so you’re just learning the terminology and exactly where they want you on the floor.

“I’m trying to pick up on it and have it stick without having to think too much on the court. I had a really good first couple weeks coming into the bubble, just getting back into the flow of things. It seems like y’all think I can play still, so I’m confident in my game. But I feel like I can take it to another level.”

Spoelstra said: “I can’t even list all of the things that he does, that any NBA coach recognizes how he impacts winning. For the short period of time, I’m really enjoying having this opportunity to coach him.”

Iguodala, who’s under contract at $15 million next season with a $15 million team option for 2021-22, has been mentoring guard Tyler Herro, who said: “I couldn’t thank him enough for what he does. Even on the court, he’s helping me make adjustments on the fly.”

Here’s my Friday piece, with Anthony Chiang, with an update on Jimmy Butler’s injury and news on Kendrick Nunn, Bam Adebayo, Meyers Leonard and more.