new york july 10 afp nba team owners unanimously approved two changes to instant replay rules on tuesday that will allow a coachs challenge and other video reviews triggered by the nba replay center the measures recommended by the nba competition committee are being used in nba summer league games and will be adopted on a oneseason trial basis for the 201920 campaign in all cases clear and conclusive visual evidence will be required to declare a call incorrect and overturn a referees decision the coachs challenge is available in a limited set of situations provided a team has at least one timeout remaining the replay center reviews were first tested at last years summer league these initiatives further strengthen our officiating program and help referees make the right call nba president of league operations byron spruell said giving head coaches a voice will enhance the confidence in our replay process among teams and fans and add a new exciting strategic element to our game enabling the nba replay center to trigger instant replay will improve game flow and provide realtime awareness of any adjustments to the score each team is allowed one challenge a game successful or not on a personal foul charged to a player on that team an out of bounds call or whistles for goaltending or basket interference a personal foul challenge can come at any point in a game but in the final two minutes of the fourth quarter or overtimes only the oncourt referees can instigate challenges for basket interference goaltending or out of bounds calls to challenge a team must call a timeout and the coach must signal the challennge by twirling a finger toward the referees the penalty for attempting to challenge without a timeout is a technical foul and no challenge to the call will be given calling a timeout to challenge an event that cannot be reviewed will cost the team the timeout but it will keep the right to make a challenge the nba replay center can instigate replays in the first 46 minutes of regulation time and the first three minutes of overtime periods for certain issues it can determine if a shot was a 3point attempt or a 2pointer or if a fouled shooter should have two or three free throws the center can also review whether or not a shot clock violation has taken place a new courtside administrator hired and supervised by the league will be added at the scorers table to expidite communication between the referees and nba replay center the administrator will not have any decisionmaking authority regarding calls or replay determinations afp bs bs