May 21st NBA Play-in Action: Memphis Grizzlies @ Golden State Warriors
Historical context aligned with market, says back Warriors cover: Golden State -4.5
With about 94% of NBA Playoff participants already identified, the Grizzlies and Warriors will duke it out Friday in the concluding chapter of the inaugural NBA Play-in Tournament for the honor of occupying the last vacant slot--the 8th seed in the West. Bookmakers originally installed the Warriors as 3.5-point favorites, but a flood of money on Golden State inflated the line as high as 5. The spread has since settled back at 4.5 over the last couple of hours though.
History suggests that the favorite is the play, and we are comfortable backing the Warriors to beat the number here.
In NBA post-season meetings between teams that both missed last year's playoff proceedings, the favorite has covered at a high rate.
In a limited sample, this system has delivered a 15% return on investment since 2005, with NO losing seasons. The observed 59% cover rate proved statistically significantly different than the 52.4% win rate required to breakeven (assuming the standard -110 vigorish) at the 90% confidence level.
We also note that the market seems to be utterly convinced the Warriors will deliver the goods Friday. As of the time of this writing, of approaching 20,000 tickets tracked by The Action Network, 82% of ATS bets and 85% of the dollar take for spread wagers are down on Golden State.
This level of herding, if it stands, would be unprecedented, back to 2015 anyway. The prior high water mark for percent of tickets for a post-season affair is 78%. And while this observation might initially cause contrarians' eyes to widen, keep in mind that bettors have been right the vast majority of times their collective conviction reached the loftiest of extremes.
The table above illustrates the six instances over the past five years where 1) NBA teams attracted at least 75% of ticket action for a playoff game, and 2) the percent of money was even higher. Backing teams in this spot delivered a hypothetical 47% return on investment, with an 80% cover rate (statistically significantly different than a 52.4% breakeven cover rate at the 90% confidence level).
Through the lens of fundamental play, we also give Golden State the edge. The Warriors rank fourth by points off longballs as a percent of total offensive output, while Memphis is pretty bad guarding the three pointer--especially the corner three (the Grizzlies rank 29th by the percentage of corner three its opposition converts). As such, we regard Curry's limitless range as a puzzle Memphis is unlikely to solve Friday.
But in the Grizzlies favor, Memphis is great on the offensive glass, and they value the basketball--while still managing to turn their opposition over. To this latter point, forcing turnovers is the cornerstone of the Grizz's above-average defense. Consider that teams' score about a point less that the League norm per 100 possessions facing Memphis, despite the Grizzlies allowing an effective field goal percentage essentially at the League average. But the Grind City crew is 7th by opponents' effective possession ratio, which hints that though Memphis does not generally force teams to shoot worse than usual, the Grizzlies impact points allowed by giving their competition fewer attempts at the basket.
The Warriors rank 22nd on the defensive glass this season, exacerbating the advantage for Memphis in offensive rebounding. Golden State is also 25th by turnovers per offensive play, and Steph Curry, generally turnover-prone despite his great stroke, has proven more careless with the ball this so far this post-season. The shooting phenom is averaging a giveaway on 19% of possessions since the regular season ended. If this propensity persists, it will play right into Memphis' hands.
So, while Memphis does not shoot particularly well, the Grizzlies boast an offense inline with the League average as a result of tenacity on the offensive board and taking care of the basketball. Similarly, Memphis' defense looks to be more predicated on taking advantage of other team's lapses (i.e. forcing turnovers) rather than on superior athleticism that results in great contests and forced misses.
In contrast, the Warriors' Steph Curry is the best basketball player in the world, per ESPN's Real Plus-Minus (RPM) statistic. The Warriors offense is indeed elite with his presence (not notwithstanding a tendency to turn the ball over), generating 116 points per 100 possessions when Curry is active, versus 111 points when their prolific guard is off the court (for perspective, the NBA average output is about 112 points per 100 possessions).
Further, Golden State's athletic defenders are more likely to bother Memphis' offensive attempts than the other way around. Andrew Wiggins, Draymond Green and Kelvon Looney all rank among the NBA's top-100 defenders, by RPM.
This view, in addition to the environmental indications cited above, compels us to lay the chalk with the home team for tonight's action.