Preston Johnson, ESPN Sports Betting Analyst 5y

Three biggest gambling takeaways from the NBA summer league

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We're a few days into the NBA summer league in Las Vegas and I've been courtside for many of the games, watching teams debut their rookies. It's become a bigger betting event every year, hitting in the slow part of the sports calendar, including this week with the MLB All-Star break.

Here are my three biggest gambling takeaways so far:


1. Shifting points totals

In the past few years of the NBA summer league, as betting lines became more commonplace, the totals in the majority of the games were lined in the 160s. There would occasionally be a line that would touch 170, but for the most part the market sat in that pocket. When the preliminary leagues began on July 1 in Sacramento and Salt Lake City, the totals were lined in the 160s. Exactly one week later, however, the totals ranged from 171 to 179. So why was there a sudden uptick in points being scored in these summer league games, and why were the early betting markets so off?

Think back to the beginning of the 2018-19 NBA regular season. In the first week, overs hit at a 31-17 clip. Teams were averaging 113 points per game compared to just 105.8 the season prior. At the time, oddsmakers had not correctly accounted for the rule change that reset the shot clock to 14 seconds after an offensive rebound instead of 24 seconds. Combined with more teams adopting a faster pace and 3-point volume going up across the league, the totals at the start of the NBA season were simply incorrect. It was one of the biggest market inefficiencies that I have seen in the last decade in a professional league.

When the summer league came around this past week, oddsmakers simply reverted to the historical lines and results of the past and used them to set the betting market. Whether they chose to ignore the significant changes at the start of the regular season or merely forgot, the mistake offered edges to bettors at a level we aren't accustomed to seeing. They made adjustments within six days time by my projections (I thought totals had corrected by Sunday), so the window didn't last very long. But those windows never last very long, and it's why maximizing those types of opportunities when they do show is so crucial.

2. Disparity in talent pool

This is the second Las Vegas summer league in a row where every NBA team was represented. Prior to 2018, only 24 teams would compete in the tournament. It may not seem like an additional six teams would impact the overall talent level in the player pool, but a few of these rosters assembled now are drastically worse than others. In addition, it is becoming more common to see the high-profile rookies skip playing in the summer league altogether.

A great example this year is a Cleveland Cavaliers team that only rosters one player with professional experience in Naz Mitrou-Long (played a total of 85 minutes over two seasons with the Utah Jazz). Everybody else on the roster is a rookie, and two first-round draft picks, Darius Garland and Kevin Porter Jr., haven't even stepped on the court. A bettor fading the Cavs this past week in summer league would be 4-1.

With more teams needing to fill summer league roster spots, the talent level of the ones that lack prior professional experience display a more significant drop-off than ever before. We never used to see summer league matchups with point spreads in the -5 to -7 range. We are now, and those favorites are still covering.

3. Team China's seesaw lines

What a story for the Chinese national team Monday night defeating the Charlotte Hornets as 25-point underdogs and as high as 40/1 on the money line. But how did we even get to that point? How did the market get there?

This is the first year that two national teams from other countries were invited to participate. Croatia and China were certainly wild cards entering summer league play, and the market reaction to their games this past week in Las Vegas has been fascinating. I mentioned the talent disparity at this point in the summer league, but oddsmakers didn't seem to consider it when lining the first set of games in Las Vegas. I understand that there is some unfamiliarity with players from Croatia or China, for example, but they can't just open China +2.5 against a Miami Heat team with NBA-level talent that had already played three games earlier that week in Sacramento. The Heat were bet up throughout the day to as high as -6.5, and they wound up winning the game by 41.

We never want to be too reactionary to a small sample size like one game, and the oddsmakers did a fairly good job of that the following night when China opened just +14.5 against the Sacramento Kings. One of the biggest moves to a point spread I have ever seen ensued, and about an hour before tip-off China was a 30-point underdog (closed +28.5). Thirty points! Even their first-quarter spread was -9 -- 2.5 points more than the closing number against Miami for the entire game. At some point we needed to realize that this was a remarkably bad overreaction to their game from the night before. It only took a quick look at the box score to realize that China shot just 30 percent from the field and that the Heat shot abnormally well from behind the 3-point line. The China spread was never really in doubt against the Kings, and China only lost the game by 17.

This brings us to Monday, when China opened as 22.5-point underdogs to the Charlotte Hornets. It appears oddsmakers chose the middle ground between the 14.5 and 28.5 from the Kings game and shaded it a little to the Hornets side since on paper they look to be better than the Sacramento team. The waiting list to bet against China wasn't nearly as long this time around, but the market did in fact move to +25 before tip-off. China won the game outright, 84-80.

We may never see anything like this again:

China Game 1: 2.5-point opening favorite Heat beat China by 41 points.
China Game 2: Kings open as 14.5-point favorites to China and are bet all the way up to -28.5.
China Game 3: 25-point underdog and 40/1 long shot China upsets the Hornets outright.

Welcome to summer league basketball.

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