How Bad Are Rookies?

Stephen A. Smith was a frustrated man on draft night. He tweeted out his dismay for New York’s Porzingis pick saying, “How in the name of decency do you spend the 4th pick on someone who may be a star in 5 years…there are players like Winslow and Mudiay who can do things for you right now?” While there may be some truth to that, as a good stat-head, you probably know that the vast majority of rookies rate very lowly. Assuming that Justise Winslow and Emmanuel Mudiay to both do something immediately that Porzingis cannot is dubious to say the least.

To find out a more detailed look at average rookie quality, I examined the last 10 years of rookies, 2nd-year, and 3rd-year players and found their Basketball-Reference.com’s Box Plus Minus statistic (Minimum of 500 minutes played).

Here is how the players are grouped:

How likely is a rookie to be a very good contributor right off the bat (at least +2 BPM)? Just 5% of all rookies fell into that category – the likes of Chris Paul (+6.1), Kawhi Leonard (+4.3), and Anthony Davis (+2.3).
Takeaway: only 5 out of every 100 rookies getting playing time contribute at a high level.

Perhaps unsurprisingly, just over 50% of rookies rate at replacement level and below. This means that more than half of all rookies getting good rotation time are worth less than a minimum contract. Some notable examples of good players in this category are Eric Bledsoe (-2.0), Andrew Wiggins (-2.3), Serge Ibaka (-2.3), and Rudy Gay (-2.5).
Takeaway: most rookies you see are going to be very-poor contributors against NBA competition.

In fact roughly 80% of rookies, 60% of 2nd-year, and 60% of 3rd- year players rate below zero.
Takeaway: eight out of every ten rookies will pull an otherwise-.500 team down.

Of course, teams have to resort to playing “minus” players all the time based on lineups and player backups. And .500 teams are always the result of players rating above and below zero averaging out. This all echoes research done by Layne Vashro and the Jeremias Engelmann/Steve Ilardi superteam, but the recycling of out-of-whack expectations means it’s always worth revisiting. But if you’re looking for someone to net your team more wins than average, rookies are not a good first place to try.

Of course, the New York Knicks are probably worse than a .500 team, so maybe Stephen A. was on to something.