The challenge system is great. Called strike three to end the game gets challenged, call gets overturned, game continues, the camera pans to the downtrodden ump, and then the manager walks out to make a pitching change. Ump had to wait another 8 mins for the game to end. pic.twitter.com/wLhKM6Klp0

Each team will have two challenges per game to call into question ball or strike calls. If the challenge is upheld by the replay, the team retains its challenge.