MLB managers only have a handful of ways they can directly impact the outcome of a contest during a game. They decide when to remove a starting pitcher, summon a reliever from the bullpen, call for a pinch hitter or ask for an instant replay from the umpires.

Just like the players themselves, some managers have better numbers than others. It’s difficult to measure the success and failure of some of those decisions, a manager’s success rate on replay challenges is readily available, thanks to Baseball-Reference.com.

In some cases, it takes skill to know when to call for a replay. In other instances, it’s just pure, dumb luck for a call to get turned in a manager’s favor. Skippers will take breaks however they can get them, but just for argument’s sake, here are the best and worst challenge success rates for managers this year.

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Who are the worst?

Craig Counsell, Milwaukee Brewers (20 percent); Scott Servais, Seattle Mariners (35 percent); Bryan Price/Jim Riggleman (36 percent)

Craig Counsell of the Milwaukee Brewers has the dubious distinction of having MLB’s worst success rate in manager challenges this season. He’s only seen seven of 34 instant replay challenges go in favor of the Milwaukee Brewers. His 34 challenges are among the bottom third in baseball and his 20 percent success rate is the lowest since MLB instituted manager challenges in 2014.

Blue Jays manager John Gibbons happily relinquishes his title to Counsell as MLB’s least successful manager in challenged calls. Gibbons held the title through the 2016 and 2017 seasons with an MLB worst 38 percent and 26 percent success rate.

Ranked slightly above Counsell in the rankings are Scott Servais of the Seattle Mariners with 13 of 37 successful calls, along with the tandem of Bryan Price and Jim Riggleman combining to go 14 for 38 as Cincinnati Reds managers this season.

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Who are the best?

Ned Yost, Kansas City Royals (77 percent); Bruce Bochy, San Francisco Giants (74 percent); Aaron Boone, New York Yankees, (74 percent);

It can’t be a coincidence that the second and third-longest tenured managers in MLB have the best success rates in manager challenges this season. For whatever reason, Ned Yost is an instant replay savant when it comes to issuing challenges. He consistently lands at the top of the list as the Royals’ skipper ranks in the top three success rates for the past four consecutive seasons dating back to 2015.

Yost is middle-of-the-pack among MLB managers when it comes to total challenges with 40 total, but he’s selective when he uses them. More often than not, Yost’s instincts are correct when he asks the umpires for a replay.

Bruce Bochy isn’t far behind with a 23-for-31 success rate on challenges this season with the Giants. First-year manager Aaron Boone has gotten into the swing of things and rounds out MLB’s top three for successful manager challenges, going 26 for 35 with the Yankees.

See the chart below for a full breakdown of how each MLB manager stacks up in manager challenge success rates this season.

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The totals