They're a perfect match -- Keuchel, a master painter on the mound, and Grandal, a premier framer behind the plate.
Here's why Keuchel and Grandal are such a great fit for each other on the South Side:
Keuchel lives on the edges
Keuchel commands the edges of the strike zone like few other pitchers. That's how he gets his outs without having high velocity.
In 2019, Keuchel threw 46.1 percent of his pitches on the edges -- within one baseball's width of the border of the strike zone, according to Statcast's pitch tracking. Keuchel had the eighth-highest edge percentage of the 161 starting pitchers with at least 1,000 pitches thrown last year.
That puts him in the top 5 percent of regular starters when it comes to living on the edges. Keuchel sat alongside such other command artists as the Cubs' Kyle Hendricks (47.5 percent) and the Yankees' Masahiro Tanaka (46.7 percent).
Since Statcast began tracking in 2015, Keuchel's edge percentage is 44.9, 15th-highest of 162 starting pitchers with at least 5,000 pitches thrown. So he's in the top 10 percent of starters over the last five years, along with other crafty veterans like CC Sabathia (45.5 percent).
Keuchel avoids the heart of the strike zone at all costs. Only 18.3 percent of the pitches he threw last season, less than one in every five, were in the interior of the zone (meaning more than one baseball's width inside the strike zone). Just check out his pitch location heatmaps from 2019 with the Braves -- where he got to pitch to another elite framer, Tyler Flowers:
Only two regular starting pitchers stayed out of the heart of the zone more often than Keuchel in 2019: Gio Gonzalez -- now Keuchel's teammate in Chicago -- and Zach Davies. Both Gonzalez and Davies were Brewers last season. Guess who was their catcher in Milwaukee?
Grandal saves his staff tons of strikes
When you throw to the margins to the degree Keuchel does, you want a catcher who can turn those pitches into strikes even if the hitter lays off. That's where Grandal comes in.
Grandal's pitch framing saved the Brewers 13 runs last season, according to Statcast's framing metric, which is based on how often a catcher gets called strikes on those same borderline pitches Keuchel loves to throw. Grandal's plus-13 framing runs was second-best of any catcher.
Most framing runs saved by catchers in 2019
1. Austin Hedges: +20
2. Yasmani Grandal: +13
2. Tyler Flowers: +13
4. Roberto Pérez: +12
5. Christian Vázquez: +11
In 2019, Grandal got called strikes on 51.1 percent of the borderline pitches he received (as in, ones that the hitter took, where the catcher's framing actually matters). The average for Major League catchers was 48.4 percent.
Since Statcast's introduction, Grandal has gotten called strikes on 51.5 percent of the borderline pitches he has received. That's fourth-best among regular catchers -- behind only Flowers, Jeff Mathis and Hedges, all noted framing specialists -- and far above the called-strike rate for MLB catchers as a whole, 46.8 percent.
A few percent above league average might not look like that much. But think about it: Grandal catches thousands of pitches a year. His framing skill adds up to a lot of extra strikes for his pitchers over the course of a season.
In all five seasons of Statcast tracking, Grandal has been a top-five framing catcher in baseball. He has averaged about 17 runs saved from pitch framing per season.
Grandal's yearly framing runs (with MLB ranks)
2019: +13 (T-2nd)
2018: +10 (T-2nd)
2017: +8 (T-4th)
2016: +28 (2nd)
2015: +24 (1st)
In 2020, hundreds of pitches could pass from Keuchel's left arm, over the edges of the strike zone and into Grandal's mitt. Grandal's the right guy to be receiving them.