Five of the six teams listed are among the best teams in baseball. They have a combined win percentage of .578.

Now take a look at the teams that have the fewest. They have a combined winning percentage of .439.

Strike Zone Runs Saved is a stat SIS developed to measure a catcher's ability to get more strikes for his pitcher than the average catcher. It looks at whether a catcher got a strike compared to the probability of the pitch being a strike, based on its location, the count and the handedness of the batter among other factors. It divides responsibility for a called strike among the catcher, pitcher, umpire, and batter. This number isolates the catcher's responsibility.

The Dodgers' success comes from an impressive combination of catchers, whom we note below. You're probably familiar with Yasmani Grandal, but Austin Barnes has been awesome in this area too.

The best defensive team in MLB, the Diamondbacks, has a unique situation at catcher, with three players splitting duties. Each has been good at getting extra strikes for his pitchers.

Jeff Mathis rates among the best in baseball at getting called strikes on pitches at the knees or just below the knees, where Zack Greinke, for whom Mathis serves as a personal catcher, often works.

J.R. Murphy got off to a strong offensive start and had good results on the defensive side as well. The latter has carried over. The former has not. Both Murphy and Mathis saved five runs with their framing. Alex Avila had poor numbers framing while in Detroit but has picked them up in Arizona. He has three Strike Zone Runs Saved.

The top two catchers in pitch-framing this season are not household names -- Max Stassi of the Houston Astros and Barnes. Stassi has a slightly higher runs saved total because of more playing time. Barnes is netting more strikes on a per-pitch basis.

Both excel at catching both the low pitch (around the knees) and the pitch on or just off the outside corner. Barnes has the highest called strike rates among catchers on those, with Stassi right behind him. Want references? Just ask Justin Verlander, who has 77 strikeouts and eight walks in nine starts caught by Stassi, or Clayton Kershaw, who has 40 strikeouts and two walks in five starts caught by Barnes.

Barnes and Yasmani Grandal ensure that the Dodgers have a catcher strong in pitch-framing starting every game behind the plate. Stassi has teamed with well-skilled Brian McCann and Martin Maldonado for a similar level of comfort in Houston.

Over the last three seasons, the premier catcher in this regard has been Tyler Flowers of the Braves, with Grandal right behind him. It’s worth noting that Flowers ranks first in Strike Zone Runs Saved despite ranking 22nd in innings in that span. Flowers has saved seven runs with his pitch-framing this season.

The trailers in Strike Zone Runs Saved are two catchers who excel in other areas -- Salvador Perez of the Royals and Tucker Barnhart of the Reds. Each has cost his team seven runs. Perez has had issues in this area throughout his career, but makes up for it by being the top catcher at thwarting basestealers. Barnhart overcomes his deficiency by being one of the game’s top pitch-blockers. They would be even more valuable if they could find a way to improve upon their pitch-framing performance.