Goal 3: Adding some size to the Bucks backcourt
The Milwaukee Bucks didn't have a great defensive backcourt last year, and some of it had to do with its size. Damian Lillard isn't a tall player, and neither was Malik Beasley. Patrick Beverley, even if he was more defensive-minded, didn't solve that problem either. Andre Jackson Jr. was the tallest and most athletic guard on the team, but he couldn't hold the team up in that regard on his own.
AJ Johnson is not only tall but also large. His 6-11 wingspan makes him potentially very disruptive at 6-foot-5. He likes defending with his arms outstretched to make that size be felt, and if he learns how to take advantage of it, he'll find another way of getting himself some minutes.
Having size on the perimeter can make for a more flexible and switchable defense, something NBA teams strongly value nowadays.
It also makes for a better rebounding team, which would be useful when Giannis is on the bench, and the Bucks are struggling a bit more to grab the other team's misses. Furthermore, it'd be easier to find a solid point of attack defender, since big and large players have more tools to make the ball-handler uncomfortable, slowing down the offense by building up a better defense.
This is, however, a bigger challenge for AJ Johnson, who might have to gain some muscle and strength to properly utilize his physicality. He won't be as impactful if he's easily outmuscled, so he needs to keep working on his conditioning. Then, after he's gained more weight and maybe grown a few more inches, he has the potential to be one of the best defensive guards in the league.
That, of course, won't be the case this year, but the Milwaukee Bucks aren't counting on that. But if Johnson can have some stretches where his impact is felt, when he makes the Bucks' defense feel more energetic and more crowded, we'll be talking about a successful first year for the rookie guard.