There's a floor-to-ceiling photo in one of the carpeted corridor of AmericanAirlines Arena, a photo that speaks to how swiftly change can come in the NBA. Dwyane Wade is in the middle, holding the Larry O'Brien Trophy from its base. On his right, LeBron James, left elbow on Wade's deltoid, and right hand on the ball of the trophy. On his left, Chris Bosh, left palm placed next to James', with a grin more expansive than the Heat's Big 3 era turned out to be.

That photo, which may not stay there much longer, is beside a door, a door that serves as the entrance to championship alley.

It wasn't the only door that was closed at media day on Monday.

Upstairs, in a sitting area in his office that overlooks Biscayne Bay, Heat president Pat Riley spoke with reporters from five outlets -- including CBSSports.com -- and essentially ruled out Bosh's return to the Miami Heat due to continued episodes related to blood clotting.

"Contrary to how this thing has been perpetuated in the media, we have worked very, very hard with Chris," Riley started. "Very hard. Our doctors were very conscientious, to the point where whoever he wanted as a second or third or fourth opinion, we talked to. We got to the point where we were heading down a road -- and were very excited -- to something we thought that would work. And then the physical simply couldn't clear him to go the next step."

And so?

"There's not a next step for us," Riley added later. "Because it's pretty definitive with us in our position from that standpoint that is probably going to be a time where we really have to step back and really confer about his future with us."

So the Heat are still working towards a return?

"We are not," Riley said. "We are not. I think Chris is still open-minded. But we are not working toward his return."

That's definitive.

And this is the definitive end of the Big 3 era.

James is in Cleveland.

Wade is in Chicago.

Bosh is in limbo, left to decide whether to fight to play again -- for someone else, if anyone else will take the risk the Heat refuse to take.

Riley? Well, he's still around, for his 22nd season with Miami, and his words still are worth reviewing. Here are four takeaways from my time with Riley Monday morning:

1. This certainly feels final

The Heat have kept largely quiet since Bosh's last major health episode, and Riley cited HIPAA privacy restrictions as well as "Section 22 Paragraph 3" of the NBA's Collective Bargaining Agreement for the team's reluctance to get too deep into medical detail, other than indicating that Bosh had been on a "six month regimen" of blood thinners that the team had to wait out. But as you can see above, there was no equivocating about Bosh's future.

And there's no communicating at the moment.

Riley and Bosh have not been talking directly, with Riley saying it was Bosh's decision not to return attempts at communication from himself, owner Micky Arison or coach Erik Spoelstra "until he got cleared." So Riley has been communicating solely with Bosh's representatives, with the primary Bosh contact recently changing.

Riley said Bosh, who was not with the team at Monday's media day, would also not be present at training camp in the Bahamas, which starts Tuesday.

While still on the team, will Bosh be sitting on the bench, like he was for certain games in the playoffs, even when not active?

"No, not right now," Riley said. "I'm not saying he (won't) in the future. But we have to sit down and have a conversation. Anytime Chris is willing to sit down and have a conversation with me, I'm more than welcome it. I e-mailed him the other day to have a meeting but did not hear back from him."

Chris Bosh on the court
Chris Bosh's basketball future is looking bleak. USATSI

2. The Heat haven't liked the way Bosh has handled this

While Riley in his opening comments said that he sympathized with Bosh's frustration and later called Bosh's efforts to play "a heroic endeavor," he made his own frustration with the situation clear, related to allegations Bosh made through Uninterrupted and others sympathetic to him have made through social media and other means.

Riley repeatedly defended the doctors, objecting mostly to the portrayal that the Heat had "written off" the 11-time All-Star.

"He wasn't just written off," Riley said. "Was not. That may have been his attitude and perception of it, because he simply didn't want to believe what was out there. In spite of that, we did everything that we could... He was never just written off. That was a poor statement on his part, really poor, because it besmirched our doctors and our efforts to help find this protocol."

Riley also lashed out at media reports -- some fed by Bosh's side -- that the Heat were concerned largely about clearing Bosh's money from the salary cap. Bosh has three years and $76 million remaining on his contract and, if he doesn't play more than nine games between now and February 9, the Heat can begin the process of trying to clear him from their roster. They would still be responsible for paying him, with insurance covering roughly half of it.

"The only thing we care about, the only thing we care about, is his health," Riley said. "That's it. And everything that's been written other than that is wrong. There's never been any kind of cap (thing).... Whatever the cap ramifications are, they are there. But we never, ever, ever thought about that. If we didn't really care about Chris, we would have played him in the playoffs this year, and tried to get past Toronto and get to Cleveland. We felt we would have had a chance."

Riley said if "there was a level of mistrust" from Bosh, "I don't know what he's talking about. Because he just simply wouldn't agree with the opinions he was getting from a plethora of doctors. It wasn't just our doctor."

3. Beyond the Heat, is Chris Bosh's career truly over?

Riley was asked again, just for clarity, if Bosh was done with Miami.

"We feel that based on the last exam that his Heat career probably is over," Riley said.

His NBA career?

"I don't know," Riley said. "That's up to him. That's up to the NBA. I can't answer that question. This is 20 months, three exams and from what's going on with 90 percent of the doctors we've talked to, that this is something where he's got to be on blood thinners the rest of his life."

Blood thinners are highly risky, because they can lead to uncontrollable bleeding if Bosh has a collision on the court.

Riley said that, while he needed to honor his own team's medical advice, he wouldn't get in the way of Bosh finding a team that feels differently,. That would, however, come with some flexibility risk to the Heat. Let's say the Heat get clearance to release Bosh in February, and then Bosh gets clearance to play from another NBA organization. Once he plays 25 games for another team, his salary goes back on the Heat's cap rather than being completely cleared.

4. Riley used a different "R" word than he typically does

Forget retooling. After reeling off a variety of incarnations of the Heat during his lengthy reign, Riley, whose teams have made the playoffs in 18 of 21 seasons. acknowledged that this latest team would take on a different look.

"Now we're on to rebuilding, I mean really rebuilding," Riley said. "But at the same time, Coach's attitude and my attitude is we want to win. And we don't know what we really have. But we love Hassan (Whiteside), we love Josh (Richardson) and Justise (Winslow) and Tyler (Johnson) and a lot of the other young players that we have, so I think from that standpoint, it's a wait and let's see what happens. And then we'll go from there. We're rebuilding now. We're not tweaking, like we did with the Big Three team. Or retooling, like we had to do right after LeBron left. We're rebuilding, but we're rebuilding to win now."

READ: What would a Heat rebuild look like?

Riley said he was "looking forward to it" and that while he "has had thoughts the last couple of years of moving on" from his role, he woke up energized. And he feels like, at age 71, he keeps getting pulled back in.

"I'm not excited about the dilemma with Chris, with him personally at all," Riley said. "But I'm excited about another season, another build, another team."

That team will have just one player -- Udonis Haslem -- who was with the Heat during its four straight NBA Finals from 2010 to 2014.

And none of the three players in that floor-to-ceiling photo, from an era gone too fast, and now officially gone for good.