There were an average of 4.6 challenges per game and 2.6 overturned calls per game.
Seven challenges were made of plate umpire Alex MacKay's calls during Arizona's 3-2 win over Colorado, and six were successful. The Diamondbacks had four of five decisions reversed and the Rockies were 2 for 2 in challenges.
MLB experimented with the ABS system during spring training last year and teams won 52.2% of their ball/strike challenges (617 of 1,182) challenges.
Each team has the ability to challenge two calls per game. Teams that waste their challenges get one additional challenge in each extra inning. A team retains its challenge if successful, similar to the regulations for big league teams with video reviews, which were first used for home run calls in August 2008 and widely expanded to many calls for the 2014 season.
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AP MLB: https://apnews.com/hub/MLB
