"As far as growing, I think that he's got unlimited growth ahead," Stevens said Saturday, per The Athletic's Jay King. "That's a good thing and a responsibility."
Tatum is averaging 16.6 points and 6.4 rebounds in 2018-19, both of which are improvements over his rookie season. His three-point shooting efficiency has fallen slightly, though, from 43.4 percent in 2017-18 to 38.2 percent.
Celtics point guard Kyrie Irving hit on a critique some have directed toward both Tatum and Jaylen Brown with Boston struggling somewhat out of the gate.
"I think last year, the young guys that are in the locker room now, some of the guys that are playing, they were a little bit younger," Irving said in mid-November with the team 9-7, per ESPN.com's Tim Bontemps. "They weren't expected to do as much, and I think that the amount of pressure that we put on them to perform every single night is something that they have to get used to, being part of a great team like this."
Last season, the Celtics were the underdogs to the LeBron James-led Cleveland Cavaliers in the Eastern Conference. When James signed with the Los Angeles Lakers, Boston became one of the favorites to win the East, yet it presently sits fifth in the conference at 20-14.
Perhaps Celtics fans got a bit carried away with how good Tatum would be after finishing third in the Rookie of the Year voting. Tatum was listed as an outsider at 150-1 to win MVP before the season started, but his odds were still only slightly worse than Jimmy Butler (100-1) and Paul George (125-1), per OddsShark.
Lofty preseason expectations aside, Tatum is playing well, and the Celtics have every reason to believe he's a foundational piece of their roster for the long term.