Utah Jazz guard Donovan Mitchell, the 13th pick in the 2017 NBA draft, is outperforming expectations this season. The 21-year-old shooting guard out of Louisville is averaging 19.5 points, 3.5 rebounds and 3.4 assists per game, hitting a robust 35 percent of his attempts from behind the three-point line. Against the Portland Trail Blazers on Sunday night, he tallied 27 points — 21 in the second half — and six rebounds, willing the Jazz to a come-from-behind victory.

I think he should be rookie of the year, for sure,” Portland’s Damian Lillard said of Mitchell after the game. “Not just because of his numbers, but his impact on their team. He’s basically leading them. It’s special to see a rookie be able to do what he’s doing out there.”

Lillard has a point. Mitchell is filling the void left after the franchise lost Gordon Hayward to the Boston Celtics and carrying an unusually high workload for a rookie. Mitchell is using a team-high 29 percent of possessions — those that end in a shot attempt, trip to the free throw line or turnover — for the Jazz this season. If that remains steady, it would be the fourth-highest usage rate by a rookie qualifying for the scoring title since the adoption of the three-point line in 1979-80.

However, as impressive as that is, it’s not enough to surpass Philadelphia 76ers guard Ben Simmons as this year’s best rookie performer.

Simmons is scoring 16.4 points per game and leads all rookies in points rebounds (7.7) and assists (7.3) per contest. His five triple-doubles this season are the most by a rookie since 1983-84, the earliest that data is available from Basketball Reference. Mitchell doesn’t have any.

According to the NBA’s tracking data, Simmons creates 16.1 potential assists (passes that would have resulted in assists had the ensuing shot been successful) per game, the fifth-most this season. Among players 6-foot-7 or taller — Simmons is listed at 6-10 — only LeBron James (17.7) creates more opportunities for his teammates than Simmons. Mitchell, by comparison, creates 6.6 potential assists per night.

Simmons is also the better defender. Synergy Sports has Simmons allowing a meager 0.76 points per possession to opposing spot-up shooters — the best mark among 27 players with at least 150 spot-up attempts defended this season — and just 0.87 points per possession when defending the rim (top 12 percent of the NBA). With him on the court, the 76ers allow 101.4 points per 100 possessions; that declines to a defensive rating of 105.3 when he is on the bench. The Jazz, meanwhile, see their defensive performance improve with Mitchell off the court.

2017-18 Defensive rating On the court On the bench Impact
Ben Simmons 101.4 105.3 3.9 points worse without him
Donovan Mitchell 104.6 103.0 1.6 points better without him

It’s that versatility on both ends of the court that makes the rookie of the year race a one-sided affair in Simmons’s favor. Per ESPN’s Real-Plus minus, an estimate of on-court impact measured in net point differential per 100 offensive and defensive possessions that adjusts for teammates and opponents, Simmons is worth 2.8 net points per 100 possessions this season, which equates to him contributing 7.1 wins to the team’s overall record. Mitchell’s 0.9 RPM is worth 4.4 wins this season.

Player Team Games played Minutes per game Offensive RPM Defensive RPM RPM WINS
Ben Simmons 76ers 53 34.9 0.5 2.3 2.8 7.1
Donovan Mitchell Jazz 54 32.0 1.4 -0.5 0.9 4.4

John Hollinger’s Versatility Index shows an even greater disparity between the two. The Versatility Index takes the product of three traditional stats — points, rebounds and assists per game — and then takes the cube root (the geometric mean) of that number so as to emphasize performing well in all three metrics rather than dominating a single one. Kyle Wagner of FiveThirtyEight modified this slightly to use points, rebounds and assists per 100 possessions instead of per game, which helps normalize for different paces of play. By this method, Simmons’s 13.5 Versatility Index is not only significantly higher than Mitchell’s (9.7), it would be the second-highest by a rookie of the year award winner since 1980; only Blake Griffin’s 2010-11 campaign (13.8 VI) would be more impressive.

2017-18 Points per 100 Rebounds per 100 Assists per 100 Versatility Index
Ben Simmons 22.7 10.7 10.1 13.5
Donovan Mitchell 30.6 5.5 5.4 9.7

The case is clear: if you want a rookie that scores a lot to win the end-of-season award, then Mitchell is your guy. If you want the best all-around rookie, Simmons is the one to beat.

Read more from The Post: