LAS VEGAS — Houston Rockets general manager Daryl Morey continues to make news by upgrading his roster and rewarding his most coveted player with more money.

James Harden agreed to a four-year extension to stay with the Rockets through the 2022-23 season. Combined with the two remaining years on his existing contract, the extension increases the overall value of Harden’s compensation to $228 million, making it the most lucrative extension in league history.

This is for a player who shut down during Game 6 of the Western Conference semifinals, but has proven to be a splendid all-around player since becoming a point guard.

Meanwhile, Isaiah Thomas will play the final year of his Celtics contract at $6.2 million, by far the biggest bargain in the NBA. Thomas agreed to a four-year, $27 million extension to join the Phoenix Suns three years ago. It was then considered a rich contract for a player who had been essentially dismissed by the Sacramento Kings.

The NBA’s economic structure is unrecognizable from even three years ago with the $24 billion influx from the new television contract. With the NBA Players Association’s refusal to allow for gradual increases in the salary cap and opting instead for immediate maximum increases, the cap has exploded from $71 million to $99 million in two years, making the contracts of Thomas and former Celtic Avery Bradley (four years, $32 million) seem like bargain basement deals.

And like Bradley, Thomas wants to be compensated for his financial sacrifices. He knows he’s underpaid. He agreed to the contract with the Suns, but will play for the Celtics next season knowing a larger payday looms on the horizon.

Actually, the Celtics could have offered Thomas an extension this summer, but because any increase would be based on his current salary, it would not have been financially prudent for Thomas to agree to a deal because more money will come when he’s an unrestricted free agent.

Thomas, who turns 29 in February, has exceeded every expectation since joining the Celtics. He has turned into a two-time All-Star, fan favorite and inspirational figure after playing through the tragic death of his younger sister, Chyna.

Thomas knows the Celtics have the financial means to reward him with a maximum contract extension. Stephen Curry just signed a five-year, $201 million pact to stay with the Golden State Warriors without hesitation from ownership. Harden is back in Houston at $40 million per season starting in 2019.

The numbers are mindboggling compared with NBA salaries just five years ago and in the NFL, where quarterbacks are essentially the only players given such rich contracts. The Celtics will have to decide if Thomas is worth the supermax and whether it is possible for the club to carry three players with maximum salaries – Thomas, Gordon Hayward and Al Horford.

Since Thomas would re-sign with the Celtics and they have his Bird Rights, he can earn more per season than Hayward and Horford, who came from other clubs. The Celtics can also offer a five-year deal to Thomas, which would take him to age 34.

Since the start of the Celtics’ resurgence 10 years ago, president of basketball operations Danny Ainge hasn’t had to pay aging players over-the-market salaries. He allowed Ray Allen to go the Miami Heat instead of offering an extension during his final season.

He traded Kevin Garnett and Paul Pierce before each of their contracts were going to expire. He traded Rajon Rondo before his contract expired and Rondo was definitely going to ask for the max.

Ainge overhauled the roster, signed players to shorter deals to create the type of salary cap space to sign Horford and now Hayward. Bradley would have also demanded a $100 million deal with the current market but Ainge decided to get compensation for Bradley and traded him Friday to the Detroit Pistons for Marcus Morris.

That decision definitely hints at the Celtics’ desire to sign Thomas to a long-term deal.

It is good news for the Thomas camp and those fans who want him to retire possibly in Boston. The money aspect will be interesting because the question is whether Thomas would accept less than the max to help the team facilitate other deals and improve, like Kevin Durant just did with the Warriors. Or will Thomas demand the max, having just watched several of his All-Star counterparts – Harden, Kyle Lowry – sign stunning, career-defining deals?

Thomas indicated during his exit interviews in late May he would perhaps sacrifice some salary for the improvement of the team, but it won’t likely be that much. Thomas deserves to get rewarded for what he has brought to the Celtics, and the team’s ownership will have to ponder how much in luxury taxes they want to pay to become a championship-caliber club.

It is to the point where fans and observers can’t automatically think a player on a maximum contract is an elite player. It has become a matter of timing and demand. The salary cap increase has created these mega deals and NBA owners have no choice but to pay these salaries to retain their best players and compete for titles.

Thomas’s turn is coming and he is eagerly awaiting next summer.

He watched his Tacoma buddy, Bradley, get shipped out of Boston because the Celtics couldn’t afford to pay him long term. So the Celtics are creating the salary cap space to make Thomas a very happy man, financially. He truly deserves it, but the money being handed out to star players is a matter of the current robust state of the NBA.

Gary Washburn can be reached at gwashburn@globe.com. Follow him on Twitter @GwashburnGlobe.