In all likelihood, the 2014-15 NBA Rookie of the Year race was settled when Jabari Parker tore his ACL in mid-December. At the time, Parker was the favorite, and his injury left No. 1 overall pick Andrew Wiggins of the Minnesota Timberwolves as the only rookie with the right combination of playing time and offensive production to win the award.
As I originally discovered last season when writing about the rookie of the year race, 26 of the past 27 ROY awards have gone to the rookie with the highest combined per-game averages in points, rebounds and assists per game. (The other one went to the second-place finisher.) If that trend holds, Wiggins is the clear choice:
But if voters look deeper, they'll discover that it's time to buck the trend and pick a rookie who's not even in the top five in combined points, rebounds and assists per game: Chicago Bulls forward Nikola Mirotic.
Making a difference on a playoff team
Mirotic's per-game averages don't leap off the table because of his limited role on a playoff team. Along with bringing over Mirotic, their 2011 first-round pick who had been starring in Spain, the Bulls also added Pau Gasol last summer to bolster a frontcourt that already included All-Star Joakim Noah and veteran Taj Gibson.
As a result, Mirotic started the season fourth on the depth chart among power forwards and centers, and on the rare occasions when the team was healthy in the first half of the season, he was the odd man out. In January and February, while suffering through a shooting slump, Mirotic averaged just 16.0 minutes per game -- less than half the 35.8 minutes a night Wiggins has played in Minnesota.
As injuries took two of Chicago's three leading scorers (Jimmy Butler and Derrick Rose) out of the lineup in March, however, Mirotic suddenly became indispensable to Tom Thibodeau. Thibodeau bumped Mirotic's playing time up to 30.3 minutes per game, and the rookie responded by averaging veteran numbers: 19.9 points and 7.5 rebounds.
Remarkably, the case can now be made that Mirotic is the Bulls' best frontcourt player, as Mike Prada of SBNation recently argued. Per NBA.com/Stats, Chicago outscores opponents by 5.9 points per 100 possessions with Mirotic on the floor, best of any player on their roster. With Mirotic on the bench, the Bulls are barely outscoring the opposition (plus-1.0 point per 100 possessions). Over a full season, that's the difference between a team playing at a 54-win level and one that would be expected to win 43 games.
No other rookie can match that impact, which is why Mirotic leads all first-year players in ESPN's real plus-minus (RPM) (because he's played so many more minutes, Elfrid Payton does have a slight edge in RPM wins above replacement, and Ben Alamar of ESPN Stats & Info has touted him for rookie of the year):
Consistently strong performance
Besides Wiggins, Payton and Mirotic, the other leading ROY contender is Nerlens Noel of the Philadelphia 76ers. After a slow start to the season, Noel has come on strong. Since Jan. 1, he's averaging 11.4 points, 8.9 rebounds and 1.7 assists for a combined total of 22.0 -- nearly as high as Wiggins' mark.
Of course, Noel's real value is at the defensive end, where his versatility is largely unprecedented. He has a chance to finish the season with a block rate better than 5.0 percent (he's at 5.0 precisely) and a steal rate better than 3.0 percent (he's at 2.9), something that's never been done before in NBA history. Hakeem Olajuwon came closest to that combination, blocking 5.5 percent of opponents' 2-point attempts and coming up with steals on 2.9 percent of the Houston Rockets' plays in 1988-89.
As much credit as Noel deserves for playing a part in Philadelphia's improvement from 27th in the league defensively in 2013-14 to 10th this season, his offense lagged behind early in the season, limiting his value. RPM has Noel rated as a bottom-five offensive player, such that despite his excellent defense he still rates below-average overall.
My wins above replacement player (WARP) stat tells a similar story. Breaking out the top four candidates for rookie of the year month by month, it becomes apparent that Noel has a strong case for best rookie of 2015 (he leads all rookies in WARP since Jan. 1). But both he and Payton rated worse than replacement level in November and December, when Mirotic was already contributing off the bench.
Quality over quantity
Mirotic and Wiggins are the most difficult rookies to compare because they've played such different roles. While Mirotic, battle-tested from the Euroleague Final Four and international competitions at age 23, was overqualified for his reserve spot on a deep Chicago team, injuries unexpectedly forced Wiggins into becoming the first option on offense for an inexperienced Minnesota Timberwolves team at age 19.
Much has been asked of Wiggins, who not only leads all rookies in minutes played (more than 400 more than any other first-year player) but has played more than anyone in the NBA since Jan. 1. Given that workload, it's neither surprising nor worrisome that Wiggins hasn't experienced the same second-half breakout the other top ROY candidates have enjoyed. Looking at the past five seasons, and taking out the lockout-shortened 2011-12 campaign, there's little to no predictive value in how much rookies improved during the second half of the season.
Wiggins' season reminds me of Kevin Durant's rookie campaign, which I covered in Seattle. Like Wiggins, Durant was asked to lead a rebuilding young team after just one season in college. Durant also struggled with the load, making a dismal 28.8 percent of his 3-point attempts and settling too often for long 2-pointers. As a result, Durant rated barely better than replacement level as a rookie before making an enormous leap in Year 2.
Like Durant, Wiggins has shown flashes of the ability to dominate games with his skill and athleticism. The comparison is particularly instructive because Durant was so talented that he could fill out his game over time. As part of his development into the MVP, Durant more than doubled his assist rate as a rookie, and nearly did the same in terms of his defensive rebound percentage. That's important because Wiggins has lagged in these areas, as well as scoring efficiency. In fact, my projection of Wiggins' college stats -- one that caused him to rank 21st overall in my draft projections -- has actually been strikingly accurate with a couple key exceptions.
Because of his role in Minnesota, Wiggins has used more plays than his college stats suggested, and done so with better efficiency in large part because he's getting to the free throw line more often. Both are positive indicators for Wiggins' future. But in the short term, he still rates as a below-replacement player because he's just an average rebounder for a shooting guard and below average in terms of assist and steal rates.
Earlier this week, I discussed the importance of durability in the MVP race. That's only true, however, when the player is performing at an above-replacement level. In the case of Mirotic against Wiggins, the gap in play is big enough to outweigh the difference in playing time. As a result, Mirotic leads all rookies in WARP by a sizable margin while Wiggins is nowhere to be found on this leaderboard:
In the long term, Wiggins has an excellent chance of proving the best rookie from this year's class. But there's little question in terms of advanced stats that Mirotic has been the NBA's best rookie this season.