NBA Summer League is underway, which means the Dallas Mavericks No. 12 overall pick in the 2023 NBA Draft, Duke center Dereck Lively II, made his Mavs debut in Las Vegas. Dallas took on the Oklahoma City Thunder and lost 91-80, but that doesn’t tell the tale of Lively’s first impressions. To do that, here are three reactions to the rookie’s debut at Mavs Summer League.

3. Dereck Lively’s Mavs Summer League debut was solid, despite the numbers

Dereck Lively II played 16 minutes in his NBA Summer League debut, and his stat line was four points, five rebounds, and one steal. His four points came on a nice dunk and 2-of-6 shooting from the foul line.

The numbers don’t sound great, but that’s OK. Lively still looked good, and we’ll get into why below. But the first thing Mavs fans need to take into account is the vast difference between the Mavs and the Thunder’s NBA Summer League squads.

Lively played with Jaden Hardy, AJ Lawson, fellow rookie Olivier-Maxence Prosper, and McKinley Wright IV. Outside of Lively and Prosper, there’s a slim chance the rest of these players will be on the team (Lawson) or play more than 15 minutes or so per game (Hardy, Wright).

On the flip side, the Thunder trotted out a lineup that could conceivably start games for the team next season with 2-22-23 All-Rookie Team selection Jaylin Williams, 2022 No. 2 overall pick Chet Holmgren, Ousmane Dieng, rookie first-round pick Cason Wallace, and Tre Mann.

The Mavs Summer League squad never had a chance in Vegas, and that’s OK. What it means, though, is that you have to find takeaways for Lively in individual moments instead of from the overall performance in the game.

And there were two takeaways on both sides of the ball that should interest the Dallas faithful.

2. Lively looked incredibly active in the pick-and-roll game

Dereck Lively II was the No. 1 high school recruit in the nation a year ago. However, injuries, ineffectiveness, and being outshined by fellow Duke bigs Kyle Filipowski and Mark Mitchell hurt the Blue Devil’s draft stock.

However, one thing that NBA scouts and, obviously, the Mavs saw was his bouncy, athletic ability, shot touch and power around the rim, and shooting potential, which make Lively perfect for the pick-and-roll game at the pro level.

Duke didn’t run a ton of pick-and-roll so that potential was largely hypothetical coming into the center’s NBA Summer League debut. Lively didn’t disappoint either, showing these possibilities in this crucial NBA offensive action.

Lively was all over the court on the offensive side against the Thunder, setting ball screens and off-ball screens all over the court. And when he rolled to the net, he was often in position to get a pass. His one field goal came on a monstrous dunk off a well-executed pick-and-roll.

Now, Lively needs to do a better job positioning and holding his screens, and some of his rolls faded away from the basket instead of going directly to it.

A lot of this can be corrected with practice, though, and will look much (much, much, much) better when Lively is running this two-man game with Luka Doncic or Kyrie Irving as opposed to Hardy, Wright, and Lawson.

1. Luka Doncic finally found his Tyson Chandler

For years, Dirk Nowitzki struggled to get over the hump. As good as the Mavs were in the regular season with the big German as their superstar, it just never seemed to work out in the playoffs.

Those Mavs’ biggest undoing was defense. Nowitzki was by no means a defensive stopper, and he never had an elite rim protector next to him (Sorry, Shawn Bradley and Eric Dampier). That all changed in 2010-11 when the Mavs brought in Tyson Chandler.

Chandler was a three-time All-Defensive Team player and a Defensive Player of the Year. He was the person who finally offered the Mavs the rim protection they needed to make up for Nowitzki’s lack of defensive prowess.

Fast forward a decade-plus later, and Dallas once again suffers from the same malady. Doncic isn’t a great defender by any means, and that hurts the team in the playoffs. Dereck Lively II could be the answer to this Mavs' problem.

Lively didn’t have a ton of defensive stats against the Thunder in NBA Summer League. But his action was felt on that end of the court. The big man altered shots all night, including one just over 30 seconds into the game that announced his presence with authority.

If Lively can become half the defender Chandler was, the Mavs were in good shape. And, like Chandler, if the center can run the pick-and-roll like the retired star did with Jason Kidd and Jason Terry, he will be even better.