THE MILWAUKEE BUCKS are on the clock.

While things seem great in Milwaukee at the moment, greatness is fragile. Yes, the Bucks posted the best record in the NBA this season, are set to play a pivotal Game 5 in the Eastern Conference finals tonight, and have a young team that looks like it can be a contender for years to come.

But all of that remains contingent on one thing: convincing Giannis Antetokounmpo, arguably the best player in the world, to remain in Milwaukee.

This is precisely the situation that spurred the NBA and the players' union to create the designated veteran contract extension -- colloquially known as the "supermax" -- two years ago. The new option allows front offices to reward their superstars earlier in their careers, while helping teams avoid the fate of the Oklahoma City Thunder (Kevin Durant) or Portland Trail Blazers (LaMarcus Aldridge), who lost superstars for nothing in free agency.

When 2020 free agency begins, Antetokounmpo will still have one year remaining on his current contract. While no other team will be able to sign him, the Bucks can present Antetokounmpo with a five-year contract extension that is expected to be worth a league-record $247 million, according to projections by Bobby Marks, ESPN's front office insider. Whether he takes it or not will represent the biggest test to the new system.

To date, four players have signed supermax contract extensions: Stephen Curry, James Harden, Russell Westbrook and John Wall. The Curry and Harden deals have worked out splendidly for both sides. Oklahoma City's ability to build around Westbrook remains unclear, while Wall's contract has become regarded as the worst in the league even before it goes into effect.

Meanwhile, Anthony Davis is currently the only player eligible to sign a supermax extension this summer. But, later today, several other players - notably Damian Lillard, Bradley Beal, Klay Thompson and Kemba Walker - could join him when this season's All-NBA teams are announced.

How they, and their teams, react will be the last test of the supermax extension. Two years after its creation, something designed to be an answer has instead created more questions.

"I mean, when you've got guys that know their talent, know their skillset, and know what they're capable of from a money standpoint, you can't really entice somebody with a bag," Paul George told ESPN earlier this season, two years removed from bypassing his own chance to chase a supermax deal. "You know what I mean?"

VERY FEW PLAYERS actually have the opportunity to sign one of these massive five-year deals. To qualify for a supermax extension, a player has to be with the team he was on at the end of his rookie contract and entering his eighth, ninth or 10th year in the NBA. He also needs to have proven he's one of the most elite players in the league, in one of three ways:

• Winning MVP in any of the three most recent seasons;

• Winning Defensive Player of the Year in the most recent season or in the prior two seasons;

• Being named to an All-NBA team in the most recent season or in the prior two seasons.

Still, there is one other factor that isn't officially listed among the rules for supermax qualification, but might be the most important of all: the player has to want to re-sign with his current team, and the team has to want to give out the contract. Because, while the supermax extension was designed to help stem the tide of superstar player movement, it quickly became clear that wouldn't be the case.

"Everybody has their own agenda, and their own motive," George told ESPN. "For me, I just wanted to play and have a chance to win a championship. I didn't care about the money. For me, it was about where can I get a good opportunity to win, and I just felt that window was closing in Indiana, and I moved on."

The biggest benefit to the rule for players is that it gives them yet another bargaining chip. The NBA has always been a star-driven league. Having one of the handful of top players in the league in a given year often is the difference between winning and losing.

It stands to reason, then, that those players will be demanding in exacting any and all answers they want about how an organization is going about its business before deciding to commit long-term -- no matter how much extra money is on the table.

After all, if the difference is between making $191 million over four years on a supermax extension or getting traded and inking a four-year deal worth $157.1 million two years from now. The total dollars are both unfathomable amounts of money.

Those could be two possible options for Beal, who is already is in the middle of a five-year, $125 million deal, if he makes an All-NBA team today.

"Money's not the problem," the Washington Wizards guard told ESPN before the end of the regular season. "It's what are we going to do here moving forward. And it starts with getting a new GM and building up our team this summer. I'll definitely give it a lot of thought. It's not an easy decision. It's not a simple one."

When Wall was deciding whether or not to sign the supermax deal Washington offered in the summer of 2017, he said he wanted to see what the team did in the offseason first. In mid-July, Wall made up his mind and signed the extension. George and Kawhi Leonard decided they didn't want to commit to the supermax deals and instead forced their way out.

Both options are still, at least technically, in play for Davis. The New Orleans Pelicans star is eligible to sign a five-year extension worth $235.5 million on July 1 -- an extension that, if he's still on the Pelicans by then, he will assuredly be offered by them. Davis has already issued a trade demand back in January -- one that his camp insists still stands.

David Griffin, the Pelicans' newly installed executive vice president of basketball operations, has insisted he is going to do everything in his power to convince Davis that he should reconsider his position on New Orleans. Griffin's argument got a boost when the Pelicans jumped to the top of the NBA draft order after winning last week's NBA draft lottery, landing the chance to select Zion Williamson next month.

Still, the power is in Davis' hands. If he continues to say that he has no interest in signing the supermax extension, New Orleans could call his bluff. But that would be an incredibly risky hand to play -- especially considering there will be any number of teams lining up to secure Davis' services if he is put on the trade block this summer.

It is that power, despite the immense dollars at stake, that still allows the players to dictate, in many cases, how these negotiations go.

"I mean, the players that are eligible, frankly, are players that are going to get paid, and they're going to have any number of alternatives," Michele Roberts, executive director of the National Basketball Players Association, told ESPN. "It hasn't hurt them. It was something that they were able to secure and they were interested in getting it and it was going to be a tremendous advantage in terms of just the amount of money.

"But I still don't see a downside. The only downside is to the extent that people absolutely believed that it was a slam dunk way to keep their guys. And it just isn't. And if they doubted it they can now take a look at Anthony [Davis] and see, 'Oh, wow, there is no way.'"

WHEN THE LATEST collective bargaining agreement was finalized in December 2016, DeMarcus Cousins and Jimmy Butler were well on their way to qualifying for the supermax extensions, which would've kept them with their current teams into the next decade. At the time, both players were amenable to signing such a deal, per sources, and locking in a massive amount of money for years to come.

Instead, the Sacramento Kings and Chicago Bulls opted to trade their cornerstones well before they hit free agency, opting for young players and draft picks over signing a current star to a massive contract as they move into their early-to-mid 30s.

This is the calculus teams have to make. It's exactly what the league wanted franchises to have the power to do.

"Part of the goal in 'early-ing' up the discussion was that those players then wouldn't reach the end of their contracts and, frankly, surprise teams by then announcing they were leaving," NBA commissioner Adam Silver said at his annual news conference last month. "The fact that a player left the market doesn't mean it was a failure, because at least in those cases the teams got value."

How much value they truly got is still up for debate. The eventual hauls for Cousins (Buddy Hield, Justin Jackson and Harry Giles) and Butler (Lauri Markkanen, Zach LaVine and Kris Dunn) were mixed, with none of the players acquired likely to be as good as the ones they were dealt for. After being widely criticized at the time of the deal, the Pacers turned out to have done well in dealing George for Victor Oladipo and Domantas Sabonis. Even then -- especially after Oladipo suffered a torn quad tendon this season -- it's hard to see that as equal value back for an MVP candidate.

For the San Antonio Spurs, trading Leonard last summer was complicated by his own injury history, forcing them to move both Leonard and Danny Green -- who have become key members of the Toronto Raptors' deep playoff run -- for DeMar DeRozan, Jakob Poeltl and what became the No. 29 pick in this year's draft. Anyone who has watched these playoffs and seen how Leonard has performed will know the Spurs would much rather have just kept him in the fold. While the Pelicans will have far less difficulty getting value for Davis this summer, the prospect of trading him -- if it comes to pass -- would be equally painful for them.

Conversely, committing to a player early can go just as wrong as moving on from him. The supermax extension Wall signed in 2017 hasn't even kicked in yet. Now the Wizards, already a lottery team, are committed to a player coming off a torn Achilles tendon for another four years at a total of $170 million, drastically limiting their flexibility to improve their roster.

That turn of events is why Washington is in the midst of a search for a new president of basketball operations to replace the since-dismissed Ernie Grunfeld -- and why teams have grown wary of handing out these contracts even in the two years since the rule was implemented.

It is hard enough to build a championship contender as it is. Building one while having a contract on the books for up to six years in the future -- and at a gigantic annual figure -- comes with plenty of additional complications. It has to be truly worth doing. Deciding which players are, in fact, worth it can be a near-impossible task for NBA front offices.

THIS WEEK, MORE teams could be faced with that decision.

And while it's a difficult decision, at least when this season's All-NBA teams are announced today, Beal, Lillard, Thompson, Walker and their teams will know where they stand.

Lillard is a lock to make an All-NBA team, and sources say, he's also likely to sign the four-year, $191 million extension if he's offered it. However, the outlook remains murky for Beal, Thompson and Walker, all of whom are on the All-NBA bubble, and might not be locks to sign a supermax deal even if they make it.

Beal will evaluate the situation in Washington, which appears headed for a full rebuild in part because of what happened with Wall. Does Beal want to sign on for that? And whoever takes over as Washington's new president of basketball operations has to decide if Beal is better as a building block making 35 percent of the cap or a trade asset.

"At the end of the day, it's not an easy decision to make," Beal said. "It's only 15 guys that make [All-NBA teams] and it's so many people who deserve it. It is what it is when it comes down to it. I try not to, like I told you before, kill myself trying to figure out if I'm going to make the team and the money and all that. Just play it out."

Walker has been the lone bright light for the Charlotte Hornets, who are arguably in the most depressing situation in the league today. Walker could make far more money if he qualifies for a supermax deal and re-signs, but will he want to?

"I have no idea," Walker told ESPN during the regular season. "I have no idea. Like I've been telling everybody, I've never been a free agent. I've never been in this situation, so I don't even know what to expect. So, yeah, I'm not sure."

Thompson, on the other hand, is widely expected to return to the Warriors on a max contract. If he becomes eligible for the supermax, though, would Golden State be willing to pay? And, if not, could that be enough to convince him to look elsewhere? Meanwhile, given only two players on a team can be on supermax contracts at a time, Draymond Green -- who is hopeful of getting an extension done himself this summer -- will be watching to see if he'd even have the opportunity to get it from the Warriors in the future.

"Ultimately, you want a system, as I've said many times, where 30 teams can compete for championships, and that relates to all aspects of the system," Silver said. "You want a system that appropriately distributes the great talent throughout the league and that teams, regardless of where they're located or regardless if they're low-revenue or high-revenue teams, can all compete on equal footing."

Some have floated the possibility of adding an extra year to what teams can offer as a further enticement for players to stay. But consider how onerous Washington's commitment to Wall already is. How much worse would it look with another $50 million tacked onto it?

Meanwhile, some on the team side have advocated solving arguably the biggest issue created by the supermax for teams -- having to decide what to do with "fringe candidates" like Wall, Beal, Walker or Thompson, who qualify by making third-team All-NBA -- by only restricting eligible players to those who win MVP, Defensive Player of the Year or make first team All-NBA. That way, the only players who could earn it would be the handful of the best players in the NBA. And yet, it's hard to see why the players association would agree to take away the chance for players to earn a significantly higher amount of money that they have already won in collective bargaining.

All of these potential solutions, and the issues they present to one side or the other, show how the dance between both sides will continue -- with the moves to come over the next year adding further clarity to a situation that still bears watching.

"I think it's pretty clear that the system, while I believe it's gotten better over the years," Silver said, "there's still room for improvement."

Additional reporting by Ian Begley and Nick Friedell.