Michael Porter Jr. and the NBA Rookies with Most to Prove in 2018-19

Some rookies start their NBA careers with a little extra pressure.

Michael Porter Jr. is one after concern spread over a lingering back injury and the former top recruit fell to No. 14 in the draft. Before he gets buried on the Denver Nuggets' depth chart and durability issues start affecting his reputation and value, he will want to quickly show coaches and the league he's healthy and back on track.

Four other rookies have more to prove than most, whether it's because of injury history or doubters who will have ammo if these players struggle to make the transition.

Michael Porter Jr. entered college viewed as a No. 1 overall candidate. By draft night, the first dozen teams in the lottery were worried about either his durability or his game since he had missed most of the season with a back injury and then struggled upon his return.

After comparing himself to a mix between Kevin Durant and Giannis Antetokounmpo (via CBS Sports Radio), Porter has plenty to prove, both to the Denver Nuggets, who are already loaded at forward, and to the rest of the league, particularly the teams that passed on him.

With Will Barton, Paul Millsap, Juan Hernangomez, Trey Lyles and Torrey Craig, Porter could lose both opportunities and value if his health continues to hold him back. He'll already be starting behind, having missed summer league and undergone a second surgery earlier in July.

Another lost season for Porter could be tough to fully come back from given how little he's played since high school and the Nuggets' presumably looking to win now with reliable, established players.

As the most decorated international teenager the NBA draft has ever seen, Luka Doncic will be out to prove his success overseas can carry over.

The hype has been building. He was taken before high-upside bigs and productive NCAA guards Trae Young, Collin Sexton and Shai Gilgeous-Alexander. In terms of competition, the strength of Euroleague over college was an often-used argument for Doncic supporters—an argument he will want to back up by showing a lack of explosion won't hold him back against NBA-level athletes.

Doncic skeptics point to his limited speed, bounce or lateral quickness for a ball-handler or wing. He will want to prove those limitations are overstated and that his skill level and intangibles more than compensate, the way they did for other international NBA stars such as Manu Ginobili, Goran Dragic and Peja Stojakovic.

No prospect created more buzz and debate than Trae Young, who led the country in scoring and assists—only with the nation's highest usage rate, suspect physical tools and below-average athleticism.

Despite his individual achievements in college, the negatives led to some skepticism regarding his NBA potential. Some scouts said they wouldn't take him in the lottery after Oklahoma's loss to Rhode Island in the NCAA tournament.

Young will be looking to prove that his numbers weren't fluky and that he's skilled, quick and tough enough to beat NBA defenders with crafty ball-handling, passing and shot-making. He will want to show he can continue producing without a green light to take 30-footers early in the clock or 19.3 field-goal attempts per game.

"I'm getting guarded like nobody else in the country is being guarded, scouted on like no one else in the country is," Young said in February, per ESPN.com's Jake Trotter. "It's a mystery coming out each and every game to try and figure out how a team is going to guard me and how I'm going to dictate how my team wins."

The specific concerns from a scouting perspective: Young's ability to separate one-on-one and finish around the trees. He made four jumpers all season that weren't threes, and he shot just 49.6 percent at the rim, per Synergy Sports.

Young also graded out in the 30th percentile defending pick-and-rolls, the 39th percentile defending off screens and the 41st percentile guarding in isolation. He will have something to prove on defense, where his effort and general ability have been questioned.

Grayson Allen has something to prove about his game, but also his maturity.

He enters the league with a reputation he's been trying to shake. Multiple tripping incidents and a meltdown on Duke's bench have earned him labels as a dirty player and hothead. And he already stirred up the anti-Allen crowd during summer league after a questionable maneuver against Trae Young that led to double technical fouls.

"It's something that comes from my competitiveness," Allen told reporters at the combine. "Competitiveness that I've had as a player, competitiveness that was pointed in the wrong direction and went over the line. It's obviously something that I needed to work on and address."

Allen had a setback-free senior season, but it's only going to take one incident to perpetuate the negative perception of his character.

More importantly, he needs to prove he can play and defend at this level. Allen was inconsistent throughout his career. After each year, there were always questions about how he'd fit, both on the floor and in the locker room.

Allen had his best season (21.6 points, 46.6 percent FG) at Duke when he was the No. 1 option (26.8 percentage usage) as a sophomore. He then shot 39.5 percent as a junior and 41.8 percent last year playing more of a supporting role to players such as Jayson Tatum, Luke Kennard and Marvin Bagley III.

He will want to prove he can be effective without being featured. Allen must show the Jazz there is value tied to his shot-making and secondary playmaking, and that he can thrive in Utah as an offensive spark off the bench.

This will mark Harry Giles III's sixth year since starting high school. He's played two full seasons in that span.

Giles tore each ACL before even arriving at Duke, where he logged just 26 games and averaged 11.5 minutes before falling to No. 20 in the 2017 draft. He then sat out the entire 2017-18 NBA season.

He will have a lot to prove this upcoming season, both to himself and those who have questioned whether he's physically built to last.

Who knows what another lost year would do to both his value and mental state?

Giles is off to an encouraging start, having averaged 10.1 points and 6.6 rebounds in 24.6 minutes between Las Vegas and Sacramento Summer Leagues. He's a key piece for a rebuilding Kings organization. But at this stage, the bar is low enough to the point where it's a win if Giles, still 20 years old, can hold down a regular rotational role without experiencing setbacks to his health.

Stats courtesy of Sports Reference.