DeMarcus Cousins is unlikely to be the Golden State Warriors’ silver bullet

By K.M. | NEW YORK

NO ONE is panicking yet in Oakland, but something isn’t quite right with this year’s edition of the Golden State Warriors. After reaching the championship series of North America’s National Basketball Association (NBA) for four years in a row and winning three of them, the league’s reigning dynasty has looked simultaneously formidable and vulnerable in 2018-19. Having just passed the halfway mark of the regular season, the Warriors have won 69% of their games, merely the third-best record in the NBA and a far cry from the 84% average they amassed over the 2014-15, 15-16, and 16-17 campaigns. They have suffered head-scratching losses on their home court to minnows like the Dallas Mavericks and Detroit Pistons, and are allowing their opponents to score more points per possession than the league average for the first time since 2012. Some of the club’s woes are due to injury—two of its stars, Stephen Curry and Draymond Green, were sidelined for close to a month. But Steve Kerr, the Warriors’ coach, is making no excuses. “This is the toughest stretch we’ve been in,” he said in November, after the club suffered a three-game losing streak. “We haven’t been in the real NBA the last few years. We’ve been in this dream. Now we’re faced [with] real adversity.”

Fortunately for Golden State fans, their creaking juggernaut is about to get a much-needed replacement part. Last July the Warriors stunned the league by signing DeMarcus “Boogie” Cousins—a four-time All-Star centre, so nicknamed for his dance-like moves with the ball—on a one-year, $5.3m deal. Perhaps the only offensive weapon Golden State had lacked in recent years was a dominating big man, capable of receiving the ball near the hoop and dunking over undersized opponents, or rebounding teammates’ missed shots and putting them back in the net. By acquiring the 6’11” (2.11-metre) tall, 270-lb (122 kg) Mr Cousins, who finished in the league’s top ten in scoring in each of his past four full seasons, the team had filled this void with one of the best. The Warriors had already proven themselves to be a near-unbeatable super-team; adding Mr Cousins to the mix risked turning the entire 2018-19 season into a mind-numbing coronation ceremony.

There was, however, a catch. On January 26, 2018 Mr Cousins tore the Achilles tendon in his left heel. He had season-ending surgery five days later, which was expected to keep him out of action for a full year. Financially, the injury could not have come at a worse time for Mr Cousins, who was just a few months away from becoming a free agent and securing an NBA-maximum contract worth over $25m a year. Without proof that the star centre would regain his prior form, no team was willing to take the risk of signing him to a long-term contract. Before reaping his payday, Mr Cousins would need to take a cheap, one-year deal to re-establish his value. And where better to do so than with the two-time defending champions?

Throughout Golden State’s bumpy start to the season, Mr Cousins has been diligently rehabilitating his heel. He is now ready to return at last, and is expected to be in the Warriors’ starting lineup for their game against the Los Angeles Clippers on January 18th, giving them an unheard-of collection of All-Star players at all five positions. With Boogie in the fold, is Golden State set to lay waste to the rest of the NBA once again?

As fearsome as the Warriors’ new starting five looks, it is far too early for their rivals to give up hope. Mr Cousins may be an unusually good player, but Achilles tendon tears are unusually bad injuries—in fact, they are arguably the worst calamity than can befall an NBA player. Not only is the recovery period long and gruelling, but there is no light at the end of the tunnel: when players do return at last, they are often merely a shadow of their former selves.

Since 1992, 24 NBA players have torn their Achilles tendons. Seven never made it back at all, though one member of that group was already 32 years old and none of the others were strong talents. The 17 that did return spanned all five of the sport’s positions, and ranged from stars like Kobe Bryant to journeymen like Jonas Jerebko. Unsurprisingly, the group averaged far fewer games played and minutes played per game in the two seasons following their injuries than they did before getting hurt. But even when they stepped on the court, the results tended to be grim.

There is no single agreed-upon measure of individual player value in the NBA, but as all-in-one statistics go, Box Plus/Minus (BPM) is one of the best. Using a simple statistical formula derived from conventional box-score statistics such as shots, points, rebounds and assists, it provides a good approximation of complex, cutting-edge metrics like ESPN’s Real Plus-Minus, which only became available in 2013. BPM is measured in easily interpretable units, the number of points by which a player would improve an otherwise average team per 100 possessions (close to the length of a standard NBA game). The average, by definition, is zero; the best player on an average team (around the 15th best in the league) comes in around four, and the league’s Most Valuable Player at roughly eight.

In general, players coming off of excellent seasons tend to fare a bit worse in BPM the next year, and those who suffered disappointing campaigns often improve. In addition, young players generally see their BPM improve from year to year, and old ones often decline. After accounting for these factors, it is straightforward to produce a projection for a player’s BPM in the season to come, based on his past performance. If players with torn Achilles tendons suffered no long-lasting effects, their BPM as a group after returning should roughly match these predictions.

In fact, they fell far short. Of the 17 Achilles victims who made it back, 15 fared worse than the projection indicated in their first year following the injury, and 14 under-performed by more than a full point of BPM. On average, the group’s performance was 2.6 points per 100 possessions worse than projected the year after the injury, and 2.1 points worse than projected after two years. For a full-time starting player, losing 2.6 points per 100 possessions would cost his team about six points of winning percentage—roughly the difference between missing the playoffs entirely and enjoying home-court advantage in the first round of the post-season.

The historical record looks even grimmer when focusing specifically on front-court players like Mr Cousins. Because such players tend to be larger, they put more weight on their fragile tendons. The seven power forwards or centres in the sample collectively performed 3.1 points of BPM worse than projected the year they came back, and 2.7 points worse the year after.

Slicing up the data by skill level does not offer much comfort to Warriors fans eithers. Six of the 17 players examined made at least one NBA All-Star team in their careers. This group actually declined more than the rest, playing 3.5 BPM points worse than projected the year after returning from injury and 3.3 points two years after. This may in fact be a more reliable measure of the true impact of an Achilles injury, since anyone short of an All-Star who loses 3.5 points of BPM would also lose his job in short order, and thus drop out of the group whose performance is being measured.

Mr Cousins was a strong enough player before his injury that even a hobbled version of him could be a valuable contributor. Even after lopping off 2.6 points of BPM, he would still project to contribute 3.0 points above average per 100 possessions. But the Warriors, already assured of a playoff berth with a high seed, will surely be cautious with Mr Cousins’s playing time in the regular season to avoid any setbacks in his recovery. And it will take far more than a part-time player at the 3.0 BPM level to return an inconsistent Golden State squad to its prior level of dominance.

None of this means that Warriors fans should sour on their would-be saviour. Last year the team sleepwalked to a “mere” 71% winning percentage in the regular season, before turning on the jets in the playoffs and winning the NBA Finals four games to zero. Golden State has already won six straight games, as Mr Curry has enjoyed a hot streak of long-range shooting and Mr Green has re-discovered some of his defensive tenacity. Bookmakers still think the Warriors have better than a 60% chance of defending their title. But they would probably be nearly as sanguine on Golden State’s chances if the team had never signed Mr Cousins at all.