
In 2021 the Texas Rangers had the #1 defensive catching tandem in the big leagues. This tandem included the services of Jonah Heim and Jose Trevino who both played at least 80 games that year. They were #1 (Heim) and #5 (Trevino) in Catcher Framing Runs and #2 (Heim)/#3 (Trevino) in Strike Rate among all Qualified Hitters in Baseball. They were both great defensive catchers for the Rangers, however their offense was a different story. They were the 4th worst wRC+ catching group in the Majors. Trevino slashed .239/.267/.340 in 302 PA while Heim slashed .139/.238/.358 in 285 PA’s. Trevino was much better at getting on base, while Heim was able to provide more of the power, doubling Trevino’s 5 Home Runs. That being said neither would find themselves being even replacement level offensively in 2021.
Regardless of how good this catching group was at defense, the Rangers made it a point to improve the offense last offseason. They went out and dished out two huge contracts to Corey Seager and Marcus Semien to improve their middle infield. Neither of these moves however, improved the catching positions offensive output. That would change immediately following the MLB Lockout. The Texas Rangers made a move to acquire Mitch Garver. Garver brought an offensive upgrade to the group. Garver had the 3rd highest wRC+ (137) among Catchers in 2021 (minimum 60 PA) while also bringing the 6th highest walk rate among catchers as well. Garver was 13th in Catcher Framing Runs and 5th in Strike Rate. While not in the top in both of those metrics like Heim and Trevino, Garver is a great offensive catcher who also brings some good defense/framing at the catching position. This was a great move for Texas since they were able to improve at a position of need while subtracting from an already upgraded position by giving up their SS Isiah Kiner-Falefa (replaced by Seager) and RHP Ronny Henriquez. This forced them to move one of their two current catchers and they ultimately traded Trevino to the Yankees for two relievers.
This left Mitch Garver and Jonah Heim at the Catching spot entering 2022. Garver, who hasn’t played at catcher since May 8th, has been just as advertised for the Rangers with a 110 wRC+ and a double digit walk rate. Heim, on the other hand, has been a game changer. Heim is not yet a qualified hitter with only 97 PA but he currently has the highest wOBA on the Rangers (minimum 90 PA) and has a slash line of .279/.361/.512 which are all team leading. He leads all catchers in wRC+ and is second in catcher WAR so far this year. In 2022 he improved his Walk rate to 11.1% from 5.3% in 2021 while dropping his Strikeout% from 20.4% in 2021 to 15.4% in 2022, putting him above average in both metrics. Defensively, Heim has continued his success there. He is 7th in Catcher Framing Runs, 2nd in Strike Rate (behind only Trevino) which puts him in the 98th percentile in Framing. Heim improved offensive output has been a great surprise for them so lets look at what allowed him to improve.
What’s New?
I’ll be the first to tell you that I am not perfect when it comes to baseball hitting mechanics but lets take a look at two Home Runs for Heim:
2021
2022
There are some slight mechanical changes Heim has made. He has his hands much lower in 2022. He moved his hands from up around the bill of the helmet to now being down around the top part of the chest. This allows Heim to create a much shorter swing and path to the baseball. This allows him to recover on any pitches he could be late on and create a more consistent swing. He also starts off with an open stance which allows him to get a better view of the pitcher and the ball. The improved ball tracking is reflected in his improved Strikeout and Walk numbers. It also appears he lands with his front foot more aligned with his backfoot than in 2021 where, when he landed, he had a much closed off stance than when he started the swing. Not a complete overhaul but these few changes that were made have improved his game dramatically. In addition to his mechanics, his approach has changed as well.
When we look at his batted ball profile in 2022 we see a few changes. He appears to be hitting the ball more up the middle rather than pulling it. Looking at his spray charts from 2021 (first image) and this year we see more of his batted balls going either up the middle or going the other way (Heim is a switch hitter so both of these images are from him hitting as a lefty since that’s the side he gets most of his PAs come from).


I didn’t include it, but his RHH heatmaps also suggest the same result. He reduced his pull rate from 43.1% in 2021 to 36.6% in 2022 while increasing his up the middle rate by 2.5% and his opposite field rate by 4.1 % in 2022. His Barrel rate of 9.9% and an Average Exit Velocity of 89.4 in 2022 are both above league average as well.
Unlike his batted ball metrics, there has not been much of a difference with his plate discipline metrics. His swing and miss rate only dropped about .3% and his contact rate went up only .1%. He has maintained his Fly-ball/line-drive rate as well so its not like he’s hitting the ball in the air more often or hitting less ground balls.
When he swings however is a different story. Heim has been able to increase his in-zone swing % by 4% here in 2022. In addition to this (and/or maybe a cause of the increase) he has increased his first pitch swing rate. In 2021, he swung at the first pitch 32 % of the time, but in 2022 it has jumped to 46% of the time. This allows Heim to attack pitches that are in the zone rather than increasing his chances of chasing at a pitch later into the at-bat. In 2021, his .248 wOBA on fastballs were the lowest out of all 3 pitching groups (off-speed/breaking), but in 2022 it jumped to .399. That is almost a .150 difference which is huge.
So why Heim?
Given that they had to make a decision to trade one of their two incumbent Catchers, there must have been a reason they chose Heim over Trevino. Heim being 26 while Trevino was 29 is an obvious answer. However, despite the results not being what Heim wanted, he had continued to hit the ball hard on a consistent basis. The problem for him was that since he doesn’t hit the ball in the air as much (15.5 LA), the only place it can go is down and since he hits a majority of the time as a Lefty he often hit the ball into the notorious LHH 3 man shift on the left side of the field. This shift was vacuuming up all of the baseballs hit their way, contributing to one of the leagues lowest BABIP in the Majors. The graph below illustrates how low his BABIP was compared to his Hard Hit %.

Despite having an above average Hard Hit %, he had one of the lowest BABIP’s in the Majors. This is where the Rangers decided to bet on Heim and have potential tapped into something with him because it is so far paying dividends. They tried to get him to spray the ball much more in 2022 to beat the shift and it has worked. Mechanically they have set him up to where he can make better decisions on which pitches he swings at while also making him more aggressive early in the count. This aggressiveness has allowed him to attack fastballs at a much better rate and improve his ability to take more walks. All this put together has pushed Heim into being one of the better Ranger hitters so far here in 2022 and potentially thrusting Heim into an AL Catcher All-Star spot in 2022.
Yes I said All-Star. Heim leads all AL Catchers in WAR (1.2) while the next two that follow are Sean Murphy and Ryan Jeffers who both have a wRC+ that are not close to league average. In fact the two best wRC+’s in the AL are both on Texas with Heim and Mitch Garver who has 110 wRC+ as mentioned earlier. Sure, Heim is not exactly a known name around baseball say like Salvador Pérez, Mike Zunino or Yasmani Grandal but the AL Catching group is not exactly the strongest of groups either. Should he continue his offensive production, Heim is deserving of a spot on the AL All-Star roster in Los Angeles as a starter.
Photo courtesy of @stathead
All stats are updated through 05 – 24 – 2022