NBA Rumors: Coach's Challenge 'Likely' Debuting Next Season on Trial Basis

The NBA will "likely" implement a coach's challenge for the 2019-20 season "on a trial basis," according to ESPN's Zach Lowe.

After being tested in the G League the past two seasons, the challenge system will be used during the NBA Summer League.

According to a league memo distributed Friday and was obtained by ESPN, plays that will be subject to challenges include:

• Called fouls
• Goaltending
• Basket interference
• Plays when the ball is knocked out of bounds.

Each of the three other major North American sports—the NFL, NHL and MLB—all employ a challenge system.

The proposed protocol would grant coaches one challenge per game, which can be used as long as the team has at least one timeout remaining. The coach must immediately use a timeout and signal to the officiating crew that it would like to challenge a play.

Like the NFL, a successful challenge would allow the team to retain its timeout, while an unsuccessful challenge would cost the team the timeout. Unlike the NFL, though, the NBA will limit the number of coaches challenges to only one (per team) regardless of the outcome of the challenge.

Under the current replay review system, NBA officials are able to go to the courtside monitors to review anything from time on the clock to out-of-bounds plays to flagrant fouls. The new system would expand the amount of plays that would be subject to review, though it would be up to the coaches to initiate the review.

In order for the challenge system to be put into effect, it must receive approval from two-thirds of the league's 30 teams. A vote is expected to be held July 9.

"Based on the feedback we have received, we expect it to be adopted," the league memo stated, per Lowe.