The Rookie Wall. The majority of first-year NBA players hit it, and it can be an upsetting and frustrating experience. It appears that Boston Celtics star rookie Jayson Tatum ran into it at some point this season.

But lately, Tatum has been playing much better, and showing why the Celtics traded down to pick him at No. 3 overall in the NBA Draft last summer. Early in the year, there even was some slight buzz about Tatum being rookie of the year.

That has dissipated of late. Tatum acknowledged recently that he hit the wall earlier in the season, and that he feels much better about his game lately, per Scott Souza of the Metrowest Daily News.

“There was definitely a period when things were just tough,” he said following Tuesday night’s 100-99 thrilling win over the Oklahoma City Thunder. “It was real tough to score. My rhythm was off. Guys were telling me there were going to be ups and downs in the season — especially my first year. Hopefully, I got that out of my system.”

In the last five games, Tatum has averaged 18.4 points. In that stretch, he had a pair of 20-plus-point outbursts in back-to-back games. He made a big 3-pointer down the stretch of Boston's clutch victory over the Oklahoma City Thunder on Tuesday.

Celtics coach Brad Stevens raved about Tatum after that game, per Souza.

“We’re going to just keep throwing him to the wolves and keep going to him in those moments,” Celtics coach Brad Stevens said. “A lot of our young guys have made big plays all year. But he certainly stepped up today and made the huge 3 when they had taken a five-point lead when he came back in the game. And, obviously, got to the rim all night.”

Tatum is still only 20 years old, and has a lot of room to grow. This outburst may not last, but it's clear that he is growing to be a very good player.