On Monday, Kansas City Royals backstop Salvador Perez went where no catcher had ever gone before when he launched his 46th home run of the 2021 season.
Like many of the long balls Perez has hit this season, No. 46 was an absolute shot with a projected distance of 429 feet. Even Johnny Bench, who had previously held the single-season record for home runs by a catcher, took a break from awkwardly holding hamburgers so he could hand it to Perez:
Johnny Bench @JohnnyBench_5
Un hombre muy fuerte! A great man. Congrats <a href="https://twitter.com/SalvadorPerez15?ref_src=twsrc%5Etfw">@SalvadorPerez15</a>. Most home runs by a catcher in a season. Catching Royal-ty. <a href="https://twitter.com/hashtag/MLB?src=hash&ref_src=twsrc%5Etfw">#MLB</a> <a href="https://twitter.com/Royals?ref_src=twsrc%5Etfw">@Royals</a> <a href="https://t.co/2lv5A6fftf">https://t.co/2lv5A6fftf</a>
If you want to get technical, Perez has hit 31 homers while playing catcher. That's only tied with Mike Zunino for the lead in Major League Baseball in 2021 and well short of Javy Lopez's single-season record of 42 in 2003.
Nevertheless, a 46-homer season by a player who spends most of his time crouching behind home plate is, well, a 46-homer season by a player who spends most of his time crouching behind home plate. A big deal, in other words.
It's thus safe to ask a question that, while straightforward, can only lead to less straightforward answers: Home runs aside, where does Perez's season rank among the best ever by a catcher?
Perez Has a WAR Problem
As any discussion of baseball history pretty much has to at this point, this one begins with a look at wins above replacement.
Royals fans know all about how WAR can be a good thing. As Joe Posnanski argued for NBC Sports at the time, it was in part because of WAR that Alex Gordon heard "M-V-P!" chants at Kauffman Stadium in 2014 even though his traditional stats lacked the sheen typically seen on the back of an MVP's baseball card.
This, however, is a different story. Though Baseball Reference puts Perez's WAR at a career-high 5.2, that same figure ranks only 93rd all-time among players who logged 51 percent of their games at catcher in a given season.
For position players, WAR's fundamental offensive component is a stat called "batting runs," an all-encompassing hitting metric that is park- and league-adjusted. It rates Mike Piazza's 1997 season for the Los Angeles Dodgers (in which he hit .362/.341/.639 with 40 homers) and Josh Gibson's 1943 season for the Homestead Grays (.466/.560/.868 with 20 homers) as the two best offensive campaigns ever by catchers.
Perez's 2021 season? It's all the way down at No. 152 with just 21.6 batting runs.
Despite his home runs, the 31-year-old has an obvious weakness as a hitter in that he doesn't get on base with much regularity. No thanks to his 4.2 walk percentage—third-lowest among qualified hitters—he's rocking just a .317 OBP this season. That's better than the average catcher (.305) yet only as good as the league average. It's also not even inside the top 500 among individual catcher seasons.
Bear in mind that what Perez has done at the plate is only one of three major aspects of his WAR. There's also baserunning, where the 6'3", 255-pounder is unsurprisingly below water with a minus-two tally, and defense, where there's good news and bad news.
On one hand, Perez leads the majors with a 45.0 caught-stealing percentage. Yet such a high mark is only worth so much when stolen base attempts are falling. He's thrown out only 18 runners, or 19 fewer than the career-high 37 he nabbed five years ago.
There's also Perez's framing, which has never been his strong suit and is now a liability. Baseball Info Solutions' data rates 2021 as the worst framing season of his career. Statcast's metrics agree and further cast Perez as the worst framer of 2021.
Let's Look at This Another Way
Then again, what WAR can't gauge is the improbability of Perez's season.
Consider the frequency of 5-WAR seasons among catchers. They used to happen all the time, often with multiple catchers achieving that status in a single year. As recently as 2014, Jonathan Lucroy, Russell Martin and Buster Posey were worth 6.4, 5.7 and 5.1 WAR.
Yet the flow of 5-WAR seasons by catchers has slowed to a trickle. Only Posey and Perez have done it since 2015, and Posey did it five years ago.
Thing is, WAR is a counting stat, and catchers don't catch as much as they used to. Whereas it used to be common in the 1990s and even into the early 2010s for a single backstop to catch 100-plus games, it's become more of a rarity in the last few seasons:
Rather than an anomaly, this is a choice. Teams want to keep their catchers on the field, so they're resting them more. This has made everyday catchers a dying breed, so Perez should be celebrated simply for playing more games (117) at catcher than everyone except Christian Vazquez (119).
As a side effect, it's not as common as it once was for a catcher to be a prolific home run hitter. Though Perez is indeed one of four backstops to cross the 30-homer plateau in the last five years, there have been only six such instances since 2004. There were equally as many just from 2000 to 2003.
Regarding Perez's home runs, there is something to be said about how they're perhaps cheapened by baseball's modern offensive standards. Though 2021 isn't on par with 2019, it's still fourth on the all-time list for home runs per game.
Yet there's nothing cheap about Perez's actual home runs.
According to Statcast, only six of his homers qualify as "doubters," or clouts that would clear the fence at seven or fewer stadiums. He has otherwise crushed his long balls, so much so that Statcast estimates he should have 49 of them. If only, say, this one, this one and this one had gone out.
So in hitting 25 home runs in only 56 games since July 24, Perez hasn't been on an unsustainable tear so much as he's been making up for lost dingers. If he can keep it up for just a little while longer, he may yet win a home run race in which he's tied with Vladimir Guerrero Jr. with Shohei Ohtani (45) hot on their heels.
Should Perez capture the lead, that would be another, perhaps no less important, historical achievement on top of his new record for home runs in a season by a catcher. He would join Bench (45 in 1970 and 40 in 1972) as the only catcher to ever lead the American or National League in home runs—though it is also worth mentioning that Gibson led the Negro Leagues in home runs 11 times during his 14-year career.
These things don't mean we should ignore Perez's shortcomings and proclaim his season to be one of the five or even 10 best ever by a catcher. The fact that he's rubbing shoulders with Bench and Gibson in this environment for players at his position, however, is fodder to at least argue for his season as the most unlikely great year by a catcher.
Where Did This Come From?
Of course, Perez is an unexpected home run-hitting superstar even in the context of his own career.
Suffice it to say he's been a different player since undergoing Tommy John surgery in March 2019. Previously, he homered in 3.8 percent of his plate appearances with a high of 27 (twice) from 2011 to 2018. Since returning in 2020, he's homered in 7.3 percent of his plate appearances and is still adding to his total this season.
He leads qualified hitters with an out-of-zone swing rate of 48.1 percent since the start of last season, so his ascent isn't being fueled by a sharper eye for the strike zone. Yet he has also upped his in-zone swing rate, and that's benefited him to the tune of a .766 slugging percentage against in-zone pitches over the last two seasons.
That Perez used to struggle against breaking balls even inside the strike zone should sound about right to anyone who regularly watched his pre-Tommy John self. Breaking stuff was his Kryptonite, as he racked up just a .217 average against it through his first eight seasons.
As for what, specifically, has changed in the last two campaigns, Perez is hitting breaking pitches higher in the zone. Which is to say he's become better at taking advantage of hangers, like so:
So, regardless of where the 2021 version of Perez belongs among his all-time catching peers, there's little question that this is the best he has ever been. And considering that he was a six-time All-Star and five-time Gold Glover just from 2013 to 2018, that is no small achievement.