Challenge Accepted: The Best and Worst ABS Catchers of 2026's First Half

[Philip Ruo]

Image courtesy of © Robert Edwards-Imagn Images / © Rafael Suanes-Imagn Images

For the 2026 season, MLB implemented the Automated Ball-Strike (ABS) Challenge System. Although the system debuted during spring training in 2025, 2026 marked its first season in competitive games. Now that the season has reached the All-Star break, catchers have had the first half of the season to get used to the system and develop strategies. Some players have emerged as some of the best (and worst) in the league at challenging calls behind the plate.

Baseball Savant provides leaderboards and summaries for all catchers’ performances, and all data referenced below can be found from their leaderboard.  

Success Rate

Success rate is measured by total overturned calls divided by the number of challenges. While this metric does not necessarily indicate overall value, it is important to get calls right when challenges are made and not waste one of the two challenges each game. However, the success rate does not account for the quality or difficulty of the challenges themselves.

Best Catcher ABS Success Rate (min. 20 challenges)

Player	Team	Challenges Won	Total Challenges	Success Rate
J.T. Realmuto	Phillies	31	39	79%
Carson Kelly	Cubs	33	43	77%
Sandy Leon	Braves	16	21	76%

Worst Catcher ABS Success Rate (min. 20 challenges)

Player	Team	Challenges Won	Total Challenges	Success Rate
Jhonny Pereda	Mariners	7	22	32%
Samuel Basallo	Orioles	17	41	41%
Brandon Valenzuela	Blue Jays	15	36	42%

Net Overturns

Net Overturns measures how often a catcher overturns calls compared with what would be expected if an average catcher had faced the same pitches. Unlike the success rate, net overturns measures a catcher’s decision-making by how they compare to other catchers’ tendencies if faced with a similar decision. This is calculated by:

(challenges won - expected challenges won) - (challenges lost - expected challenges lost)

Best Catchers In ABS Net Overturns (min. 20 challenges)

Player	Team	Challenges Won vs Expected (+ is good)	Challenges Lost vs Expected (- is good)	Net Overturns
Dillon Dingler	Tigers	9.7	-13.2	23.0
Hunter Goodman	Rockies	17.8	-2.4	20.2
Victor Caratini	Twins	21.3	6.3	15.0

Worst Catchers In ABS Net Overturns (min. 20 challenges)

Player	Team	Challenges Won vs Expected (+ is good)	Challenges Lost vs Expected (- is good)	Net Overturns
Samuel Basallo	Orioles	-15.6	3.8	-19.4
Edgar Quero	White Sox	4.4	23.4	-19.0
Carter Jensen	Royals	-12.9	1.1	-14.0

Net Runs

While it is important for calls to be overturned, it is also important that teams are able to generate value from those challenges. Baseball Savant assigns a run value for all challenges. This metric accounts for the direct impact of a challenge. A successful challenge with the bases loaded and two outs will carry a different run value than the first pitch of an inning.

Best Catchers In ABS Net Runs (min. 20 challenges)

Player	Team	Net Runs For
J.T. Realmuto	Phillies	1.5
Carson Kelly	Cubs	1.5
Tyler Stephenson	Reds	1.1

Worst Catchers In ABS Net Overturns (min. 20 challenges)

Player	Team	Net Runs For
William Contreras	Brewers	-3.8
Drew Millas	Nationals	-3.6
Edgar Quero	White Sox	-3.6

Outcome Flips

Catchers can help out their pitchers by saving their challenges for important times in the count. Removing walks or adding strikeouts can not only improve a pitcher’s box score but also dramatically impact a team’s win probability and overall success in the game, depending on the situation. Since this is a counting metric, it would be unfair to highlight the fewest flips.

Best Catchers In Outcome Flips (min. 20 challenges)

Player	Team	Strikeouts Flipped	Walks Flipped
Shea Langeliers	Athletics	20	8
Victor Caratini	Twins	17	6
Hunter Goodman	Rockies	17	4
Tyler Stephenson	Reds	17	4

Reasonable Challenges

According to Baseball Savant, a "reasonable" challenge opportunity occurs when at least one of the following is true: The original call was incorrect; the pitch is within 3 inches of the strike zone edge and an overturn would gain at least 0.3 runs; the pitch carries an expected challenge rate of at least 20%.

Reasonable challenges would indicate if a player is choosing the correct pitches to challenge and not needlessly wasting them on low-probability decisions. A challenge classified as  “unreasonable” would certainly result in a confirmed call. Catchers need to balance making sure that their challenges are reasonable when taken, and not missing out on challenges that could have been overturned.

Best Catchers In Reasonable Challenges (min. 20 challenges)

Player	Team	% Challenges Considered Reasonable	% of Reasonable Challenge Opportunities Taken
Mitch Garver	Mariners	87%	27%
Hunter Goodman	Rockies	86%	35%
Sandy Leon	Braves	86%	38%

Worst Catchers In Reasonable Challenges (min. 20 challenges)

Player	Team	% Challenges Considered Reasonable	% of Reasonable Challenge Opportunities Taken
Drew Millas	Nationals	49%	21%
Brandon Valenzuela	Blue Jays	50%	15%
Johnny Pereda	Mariners	50%	23%

Verdict

Which catchers stand out when combining all of these aspects?

Best Overall ABS Catcher: Hunter Goodman - Rockies

Goodman consistently ranked among the league leaders across nearly every metric. In the metrics where he fell outside of the top three, he ranks 13th at 67% (while having a larger sample size than all but one of the catchers ahead of him) and 4th in net runs with 0.9 runs. His strong decision-making and ability to reverse key outcomes led him to be one of MLB’s top performers in ABS challenges.

Worst Overall ABS Catcher: Drew Millas - Nationals

Millas is the only catcher who challenges fewer than half of the reasonable challenge opportunities. Despite having the 16th-most challenges (out of 62 catchers with at least 20 challenges), he only has four flipped calls. Only three catchers in this group have fewer flipped calls than he does. He has the second fewest net runs, but the leader Contreras has 60 more challenges than Millas, with only 0.2 fewer runs. Millas was also in the bottom five in both net turnovers and success rate. He will look to improve in these areas going into the second half of the season.

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