Pitch framing has been part of baseball for generations and will remain one until the day robo umps take over calling balls and strikes. And framing is not a particular strength of either the Cubs or White Sox.

There’s no way of knowing for sure if it was a factor when umpire Jordan Baker blew the ball-strike call that led to the ejection of pitcher John Lackey and catcher Willson Contreras in Friday’s 8-2 Cubs victory over the Cardinals.

What can be said is that the call fits a pattern in which Chicago catchers have a higher than average percentage of pitches in the strike zone called balls and a lower than average percentage of pitches outside the strike zone called strikes.

Quantifying the effect of framing has been eased by electronic pitch tracking systems. You can find data going back to 2007 here.

Willson Contreras | Jon Durr/Getty Images

Of the 6,891 pitches Contreras has received, 124 fewer than average have been called strikes. That translates to -16.4 runs above average, according to the StatCorner data. Alex Avila also has been a below average framer in his Cub days, at -17 calls and -2.2 runs in 1,698 pitches.

That’s a contrast to 2016, when the Cubs were one of the better framing teams in baseball. Miguel Montero was third in MLB with 16.1 RAA and David Ross 10th at 8.7.

This year’s White Sox also have had framing woes, with Omar Narvaez’s -21.1 RAA better only than the Royals’ Salvador Perez (-24.7) and the Tigers’ James McCann (-28.4). Kevan Smith also is on the negative side at -8.1.

The numbers are broken down into pitches in the zone called balls — the zBall% — and pitches outside the zone called strikes — the oStrike%.

In Contreras’ case, 16.6 percent of the pitches he’s received in the strike zone are called balls. Of the 39 major-league catchers with at least 4,000 pitches received, Contreras is tied for the 10th highest zBall%. Baseball’s best at 11.4 percent is the Orioles’ Caleb Joseph.

The other side of the coin is the OStrike%, and Contreras has just 6.5 percent of pitches outside the zone called strikes. That’s tied for eighth lowest in MLB, with ex-White Sox Tyler Flowers leading baseball at 12.3 percent for the Braves.

Overall, Cubs pitchers lose an average of 1.38 percent strikes per game when Contreras is behind the plate, compared to MLB average. Flowers is the leader at plus-2.53 strikes per game, and he also leads MLB with 26.5 RAA.

Contreras is an extremely valuable player. His 3.8 WAR at baseball-reference.com is tied for the MLB lead among catchers with the Giants’ Buster Posey and the Yankees’ Gary Sanchez, and his .872 OPS trails only Sanchez’s .887 among catchers with at least 300 plate appearances.

He’s strong overall behind the plate with a 1.2 defensive WAR that ranks sixth in MLB.

But the framing component of Contreras’ defense is a work in progress, and an important one until the robo umps get here.

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