Coach's Challenges Are Coming to the NBA; Here's They'll Work

For the first time in league history, the NBA is implementing coach’s challenges, putting the NBA in line with several other pro sports leagues.

The NBA’s Board of Governors approved the change on Tuesday evening. The NBA has used this version of its challenge system in the G-League over the last two seasons and tinkered with it a little bit during last summer.

Sources: The NBA Board of Governors have passed the implementation of in-game challenge flags for head coaches for the 2019-20 season.
— Shams Charania (@ShamsCharania) July 9, 2019

Here’s how it’ll work:

Coaches will get one challenge per game, regardless of whether the challenge is successful or unsuccessful.
Teams must have a timeout remaining to request the challenge and must call for it immediately after the reviewable event takes place. They’ll “twirl his/her index finger toward the referees” to signal for the challenge.
If the challenge is successful, the team will keep its timeout. If not, the timeout will be used.
The following calls can be challenged:
There must be clear and conclusive visual evidence that the original call was incorrect.
No calls will be allowed to be reviewed in the final two minutes of the fourth quarter or overtime
The crew chief in the game will determine the final outcome of the challenges involving fouls while the NBA Replay Center in Secaucus, New Jersey will decide the other reviewable calls.
All technical and flagrant fouls that occur during or right after a call being challenged will stand regardless of the result of the challenge.

The league is also leaning toward replay reviews coming from the review center in Secaucus, New Jersey without the involvement of the on-court officiating crew, an idea similar to the NFL’s booth reviews. The NBA wants to give Secaucus the authority to review questionable two or 3-point shots without the officiating crew asking for it, as well as shot-clock violations. This replay review center will also have the ability to trigger an instant replay review.

Sources: Besides approving coach's challenge, Board of Governors approved replay center's ability -- in addition to game refs -- to trigger instant replay. Approved circumstances include whether it's a 2 or 3 point FG; and if a shot was made prior or after the shot clock expired.
— Adrian Wojnarowski (@wojespn) July 10, 2019

A courtside administrator would be added to the scorer’s table to act as a middle-man between the replay center and the crew at the game, along with someone to announce scoring changes.