Attention to all NBA Summer League haters: Quit it. Just stop. Now.

Despite the view of Summer League naysayers, the Association's pre-preseason tournament isn't a collection of pickup games in which Rookie Number One tries to out-dunk Rookie Number Two for no reason other than it's cool.

No, the Summer League is about learning. It's about growing. It's about securing a job.

To some players, it means everything.

All of which is why these July performances can't be dismissed. For instance, on Sunday night, prized Boston Celtics rookie Jayson Tatum had himself a stinker of a game, racking up only 11 points on 4-of-11 shooting from the field.

It was a sharp contrast to Tatum's previous outing. On Saturday, in an 86-81 victory over the Los Angeles Lakers, Tatum was a beast, scoring 27 points and ripping down 11 boards.

What happened?

Well, as Tatum explained to ESPN, he was pooped: "The back-to-back, the quick turnaround, I definitely felt it today, sluggish and tired."

So now we all know Jayson Tatum needs to work on his conditioning. This is a big deal, and begs the question, what else have we learned since the Summer League kicked off on July 1?

Lonzo Is Learning

In his maiden NBA voyage on Friday night, Lakers first-round pick Lonzo Ball was less than good.

In the Lakers 96-93 OT loss to the Los Angeles Clippers, he managed only 5 points, hitting just 3-of-15 shots, and only 1-of-11 three-point attempts. His 5 assists and 4 rebounds didn't soften the blow.

To his massive credit, Ball shook it off the following night and dropped a Rajon Rondo-esque triple-double with 11 points, 11 rebounds, and 11 assists in that aforementioned loss to the Celtics.

The two takeaways from his up-and-down weekend were that Ball has enough chutzpah to put a heinous game behind him -- a great characteristic in a rookie -- and considering that his shooting percentage over those first two games was 28.6%, dude needs to work on his jumper.

Dante Exum Is Ready

This week's Utah Jazz isn't last week's Utah Jazz. Not even close.

Last week, we learned that next season, former Jazz forward Gordon Hayward will be wearing a Celtics uni, and newcomer Ricky Rubio will be manning the point. But if third-year guard Dante Exum can bring his Summer League game into the regular season, Hayward won't be missed. (Okay, he'll totally be missed, but maybe not quite as much.)

In his three outings, the 21-year-old has averaged 20 points, 6.3 assists, and 4.3 rebounds in a paltry 27.3 minutes. He was flat-out brilliant on Wednesday in a 100-94 win over the Philadelphia 76ers, delivering a monster stat line of 26 points, 10 dimes, and 5 boards.

Exum won't take over the starting point guard spot from Rubio, but man, wouldn't the 6'6" Aussie look good in Utah's two-spot?

The Hawks Stole John Collins

Coming into the NBA Draft, scouts were divided on John Collins.

Some felt the power forward out of Wake Forest was a low lottery pick, while others slotted him as a second rounder. Turns out he was right in between those two extremes, and was grabbed by the Atlanta Hawks with the 19th pick.

Based on his first two Summer League outings, the lottery might've been a more logical launching pad.

The long 6'10" 19-year-old has shown a nose for the ball -- we're talking 21 rebounds in his two games -- and the ability to put the rock in the basket -- we're talking 11 field goals on 15 attempts.

With the loss of free agent Paul Millsap, there will be plenty of minutes available at the Hawks power forward spot, and if Collins can show this sort of moxie come training camp, those minutes will be his for the taking.

Jaylen Brown Needs Big Minutes

Celtics swingman Jaylen Brown had a decent rookie year, putting up respectable per-36-minutes numbers of 13.8 points and 5.9 rebounds.

Celtics swingman Jaylen Brown has had a scary Summer League, putting up killer per-28.5-minutes numbers of 17.5 points and 10.5 rebounds.

Brown is legit and needs to see the floor, but the Celtics' oddball roster might not allow him to get his proper burn. A natural small forward who can play some shooting guard, Brown will be battling fellow position-hoppers Hayward, Tatum, Marcus Smart, and newly-acquired Marcus Morris for playing time. (If the Celtics don't have to get rid of Jae Crowder in the inevitable roster purge that will allow them to afford Hayward, you can add him to the list of bodies standing in Brown's way.)

After seeing this sort of inside/outside domination from his second-year man, C's coach Brad Stevens can't let Brown languish on the bench. He just can't.

Bryn Forbes Can Score

The San Antonio Spurs' scouting department is sick. If they think there's something there, there's probably something there.

Second-year Spurs combo guard Bryn Forbes looks like he has something there.

In his rookie campaign last season, Forbes didn't see much run -- he played in just 36 games, averaging 7.9 minutes a night -- and other than a late-season game against the Dallas Mavericks in which he scored 27 points in 28 minutes, he didn't leave much of an impression.

But on Sunday, this happened.

Impression made.

In his 35-point explosion against the Sixers, Forbes hit 8-of-19 from the field and was a perfect 17-of-17 from the charity stripe. He's led the Spurs in scoring in all three of their Summer League tilts, averaging 21.3 points in 29.7 minutes.

Admittedly, Forbes is a one-dimensional player -- he scores, and that's pretty much it -- but considering that in the Western Conference, San Antonio will have to deal with massive point totals from the World Champion Golden State Warriors and the retooled Houston Rockets, some instant offense off of their bench will be crucial.

These kind of discoveries are why the NBA Summer League is important.