The Golden State Warriors' shooters are experts at their trade; their 10,000 hours spent working on their craft has trained them to be highly sensitive to its tools.
During a first-round playoff game against the Denver Nuggets in April, Jordan Poole thought something wasn't right with the basket. First he asked his teammates, and then he alerted arena officials.
"Nobody else really saw it," Warriors teammate Stephen Curry said. "They actually checked, and it was off center by like an inch."
Before Game 3 of the NBA Finals in Boston last week, once again Warriors players were examining the basket with concerned looks about two hours before tipoff. It didn't quite look right to them and, after asking for it to be checked, the basket was slightly higher than the required 10 feet.
"Players have a really sharp eye for that," Warriors coach Steve Kerr said after the error was found. "Players can tell."
Despite these examples, the NBA, though, doesn't rely solely on players' feel. It has a detailed and old-school system in place to monitor the most basic aspects of the game, like the hoop being 10 feet off the ground, and the nuanced details, such as how tight the rim is.
The same specialist, a consultant with the league named Drew Sorenson, has been traveling to all 29 NBA arenas and calibrating the rims for the league for around 30 years. If a point has been scored on a hoop in the NBA, or even the backup stanchion that hides in the arena tunnels in case of emergency, Sorenson has been the one to examine it with his kit of tools and instruments.
The league sends its expert representative to every arena in the preseason to check everything from the height of the bench seats to the setup of the scorers table. Then around midseason, everything is checked again. Then Sorenson goes to all playoff arenas to check those things the average fan would rarely think about.
Before the start of the Finals, Sorenson was in San Francisco to monitor the hoops at Chase Center, and then he flew to Boston to make sure the rims at TD Garden could withstand the NBA standard of 200 pounds of force without bending, which he tests with meters and low-tech weights.
The league is aware of several metrics it tracks, for example: What is the rim flex, rim pressure and rebound percentage, the amount of bounce the ball has coming off the rim?
"The rims are locked at a certain percentage of give," said Chris Boghosian, an NBA associate vice president of basketball operations who oversees arena equipment. "Even if the measurements are determined to be a little of out of range, the average person wouldn't even be able to tell. But we keep an eye on it to make sure we catch and correct any issues."
There's a lot going on with NBA baskets. Both video and still cameras are affixed all over them. During the Finals, there are at least three TV cameras on board every basket framework, plus a 360-degree virtual reality cam. There are also microphones and huge spools of wiring and remote controls.
This is one of the reasons Sorenson uses levels to make sure the rims are flat and plumb bobs to check to make sure the backboard is vertical. With all of the equipment attached, there are times when things can get out of whack.
In the wake of the basket being too high before Game 3 of the Finals, NBA and TD Garden officials have stepped up their monitoring. They checked basket measurements after the teams practiced the day after. Then, they did so again hours before Game 4 on Friday night at TD Garden, after the Celtics' trampoline dunk team went through its practice and abused the rim of the hoop that had been found to be a little off.
Many NBA players believe this process, other than the rare moment when things might be off, works to create consistency with the rims around the country -- unlike their high school, AAU and even college days when players never quite knew what they were going to get when they stepped on the court.
"It's rare [there's a difference]. They all seem 10 feet. They all seem the same size and circumference," Warriors guard Klay Thompson said. "These have a little more give than the rims I grew up playing on. Especially compared to the rims at recess, those double rims. Those things are stiff."