Salvador Perez and the Kansas City Royals have been baseball's best at utilizing their robot challenges through the first weekend of the Automated Ball-Strike System.

Perez topped all catchers by going 4-0 on challenges, while San Francisco's Heliot Ramos and Cincinnati's Eugenio Suárez were the only batters who went 2-0 — Suárez won his appeals on consecutive pitches. Three-time MVP Mike Trout of the Los Angeles Angels is 3-1 on challenges.

Atlanta’s Ronald Acuña Jr. was the only batter who went 0-2.

Kansas City and Arizona were the only perfect teams, with the Royals 4-0 and Arizona 3-0. Houston was 0-6 and St. Louis was 0-3.

Many teams have tried to save their challenges for high-leverage situations.

“1-1 counts. Counts that are going to end the at-bat. Those are big challenge times,” said Phillies manager Rob Thomson, whose team went 4-3.

Challenges had a 53.7% success rate through 47 games. There were 175 challenges, an average of 3.7 per game.

Catchers succeeded on 59 of 92 challenges for a 64% rate, but batters on 33 of 78 for a 42% rate. There were just five challenges by pitchers, with Baltimore's Ryan Helsley and the Athletics' Hogan Harris winning, and the Los Angeles Dodgers' Edwin Díaz, Houston's Roddery Muñoz and Philadelphia's Zach Pop losing.

Cincinnati batters went 6-0, while Braves batters were 0-4.

C.B. Bucknor had the poorest ABS results among umpires when six of eight challenges of his calls were successful during Cincinnati's 6-5, 11-inning win on Saturday. All six overturned calls involved strikes being changed to balls. The two confirmed calls involved a ball and a strike.

Boston's Alex Cora was ejected in that game by Bucknor for arguing a checked swing call.

“I feel bad for them because everybody has a bad day," Thomson said of the umpires. "The last thing you want to see is somebody get embarrassed. I don’t care who it is, player, coach, umpire. I don’t want to ever see anybody get embarrassed playing this game.”

Minnesota’s Derek Shelton became the first manager ejected for arguing an ABS call on Sunday. He was tossed in the ninth inning of a game against Baltimore after complaining that Helsley waited too long to signal for a review.

Under the ABS system that started this season, teams can appeal strike zone decisions to a system based on 12 Hawk-Eye cameras that measure whether a pitch crosses the strike zone with accuracy of about one-sixth of an inch.

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AP Sports Writer Dan Gelston contributed to this report.

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