ESPN's Brian Windhorst reported on SportsCenter that the Celtics will "most likely" make a max contract offer to Tatum:
"If Jayson Tatum is the superstar that they envisioned when they began this whole rebuilding process when they traded Kevin Garnett and Paul Pierce for all of those draft picks hoping to land a player like this, we could see 'Glory Days' for the Celtics again. But it's very much up in the air, and I'm gonna tell ya, they're gonna have to pay him like it because after this season ends, he is going to get most likely a max contract. They're going to bet that he becomes that player."
The Celtics have done a good job of prioritizing their homegrown core players. Marcus Smart signed a four-year extension in the summer of 2018.
Prior to the deadline last October for players to sign rookie-scale extensions, Jaylen Brown received a four-year deal worth $115 million.
Tatum is set to earn $9.9 million next season on his rookie deal, per Spotrac.
One potential complicating factor for Tatum is the uncertainty around the NBA salary cap due to the coronavirus pandemic. ESPN's Adrian Wojnarowski reported in January the cap projection for next season was $115 million.
Earlier this month, Marc Berman of the New York Post reported the 2020-21 cap will "for sure" be lowered. Max extension values are based on 25 percent of the salary cap, with the ability to increase based on incentives like making an All-NBA team or winning MVP.
Tatum has established himself as the key to Boston's present and future this season. The 22-year-old was named to the All-Star team for the first time. He leads the team with 23.6 points per game, ranks second with 7.1 rebounds per contest and is shooting 39.8 percent from three-point range.