A lot of money was spent on free agents and contract extensions this NBA offseason, but one key contract decision everyone was waiting for revolved around All-Star Jaylen Brown and the Boston Celtics. Entering the final year of his current contract, Brown was eligible for a massive extension after receiving All-NBA honors. With the league's salary cap increasing and Boston not wanting to let their star go, the 26-year-old cashed in on a historic deal.

On Tuesday, the Celtics and Brown agreed to a five-year, $304 million contract extension that keeps him under contract with Boston through the 2028-29 season. This new contract is fully guaranteed, there is no player option in the final year and best of all for Brown, he now becomes the highest-paid player in league history.

The five-year supermax extension Brown received surpasses the $276 million contract two-time league MVP Nikola Jokic signed with the Denver Nuggets to become the league's highest-paid player just last year. In back-to-back offseasons now, a new star has earned the NBA's richest contract ever. Looking ahead, Brown may not hold this title for too long, as his partner in crime with the Celtics may wind up dethroning him with a possible contract extension he will see in the very near future.

So how long will Jaylen Brown hold the record for the biggest contract in league history and which NBA superstars could see even more money on their next contracts? All three players currently reside in the Eastern Conference and none of them should come as a surprise to anyone, as they are amongst the best of the best this league has to offer.

Jayson Tatum – Boston Celtics

Boston Celtics, Jayson Tatum

Jaylen Brown will have to look no further than a couple of seats in his own locker room to find the next player in line for a massive contract extension. While Brown earned All-NBA Second Team honors this past season, Jayson Tatum earned All-NBA First Team honors for the second consecutive year and had his best season of his career, averaging 30.1 points and 8.8 rebounds per game.

Tatum has been the face of the Celtics over the last few years and is the reason why this organization is once again hunting for championships. At 25 years old, Tatum is still growing into one of the best players in the entire league and entering the new season, the Celtics star is only under contract through the 2024-25 season, not including his player option for the following year.

He will be eligible for a supermax contract extension heading into next offseason and seeing as they just gave Brown a massive deal, it is not hard to believe the Celtics will instantly do the same with Tatum when he becomes extension-eligible. According to ESPN's Bobby Marks, Tatum's upcoming extension could wind up being in the ballpark of $338 million over the course of five seasons if the salary cap was to jump 10 percent over the next two seasons.

The Celtics are not going to let Tatum walk away as a free agent any time soon and there is no chance that they would trade him before exploring the idea of trading away Brown instead. Tatum is the best player on Boston's roster and it would not be surprising to see him spend his entire career wearing green.

Being as young as he is and playing at an extremely high level, Tatum is on a collision course to receive a larger contract extension next offseason than his counterpart Brown received this summer.

Donovan MitchellCleveland Cavaliers

Unlike the Celtics' situation with their two stars, Donovan Mitchell's situation with the Cleveland Cavaliers is still open for interpretation. Mitchell has loved everything about the Cavs since being traded to Cleveland last offseason and in his first year with the organization, he led them to 51 wins.

The 2022-23 season ended up being the best year the Cavaliers have had since the 2016-17 season with LeBron James and the 1992-93 season without LeBron. This past year also ended up being the best of Mitchell's career, as the 26-year-old star averaged 28.3 points and 4.4 assists per game while shooting 48.4 percent from the floor and 38.6 percent from three-point range.

Like Jaylen Brown, Mitchell was named to the All-NBA Second Team and he has rapidly grown into one of the best scoring guards in the entire league. If you need any proof of this, just go back and watch his performance from January 2, as the Cavs guard dropped 71 point in an overtime win against the Chicago Bulls. This is tied for the sixth-highest scoring game by a player in league history.

There is no denying that Mitchell is one of the best guards of this generation, but his future is very much up in the air and the 2023-24 season will be very telling as to what the Cavaliers could potentially achieve. His contract is exactly the same as Tatum's right now, so he could potentially be with Cleveland through the 2025-26 season if he was to pick up his player option. Then again, he will be eligible for a supermax extension next offseason and the Cavs will have a decision to make.

If they do not wish to offer him one of the largest contracts in NBA history, Mitchell may very well walk away from the Cavaliers and seek a trade to a team willing to pay him like the top-tier talent he is. Just entering the prime of his career and proving that he can be the best scoring option on his team, Mitchell is absolutely the type of player that can lead a franchise to the NBA Finals. Whether or not he will do so with the Cavs is yet to be seen.

Giannis AntetokounmpoMilwaukee Bucks

Milwaukee Bucks, Giannis Antetokounmpo

Jaylen Brown received a massive contract and both Jayson Tatum and Donovan Mitchell will be getting $300 million deals as well in the near future, but Giannis Antetokounmpo will absolutely become the highest paid player in NBA history when he gets a new contract. Entering Year 3 of a five-year, $228 million contract he signed in 2020, Giannis is eligible to receive an extension right now.

However, the Bucks can only offer him a three-year, about $170 million extension. If he waits until next offseason, the money around the league is only going to increase and so will Antetokounmpo's value. A two-time MVP and an All-Star for seven straight seasons, Giannis will be able to get a supermax deal from the Bucks, as well as any other team around the league who wants to get their hands on him.

He may have just finished up his 10th NBA season, which is hard to believe in itself, but The Greek Freak is still just 28 years old and is entering the best years of his career.

This is another scary thought in itself!

Just imagining Antetokounmpo getting better and stronger is not doable, as many seem to think he is the best player in the world right now. It's unlikely Milwaukee will ever willingly let him walk away, but Giannis is a smart business man and by not signing an extension this offseason, he is putting the Bucks on the clock.

Whether it is now, next offseason, or in 2025, Antetokounmpo is still going to be one of the faces of the NBA. This is why his value is only going to increase over time. As the league's cap numbers continue to grow, Giannis continues to be in line to receive a historic contract that may wind up coming close to $400 million in total compensation.