J.T. Realmuto has been a Phillie for one day and you've probably already heard a few dozen times that he's the best catcher in baseball.
In a column in support of the trade Thursday, I referred to Realmuto as the only catcher in baseball you could argue possesses all five tools.
Let's elaborate ...
Receiving and blocking the ball
This feels like the right place to start, given Jorge Alfaro's glaring deficiencies catching the baseball in 2018.
Realmuto blocked 90.5 percent of potential wild pitches last season, according to Sports Info Solutions.
Alfaro blocked 86.5 percent.
May sound like an insignificant difference, but Alfaro's rate was the worst among all major-league catchers. And truthfully, the percentage could've been even lower considering some of the balls Alfaro missed weren't even potential wild pitches.
In terms of runs saved by blocking balls, Realmuto ranked ninth among all big-league catchers with at least 3,000 chances last season.
Alfaro ranked 112th out of 115 catchers.
Alfaro's arm was the strongest among all MLB catchers last season, per Statcast, at 90.8 mph.
Realmuto ranked second at 87.8 mph.
In 2016 and 2017, Realmuto ranked third. In 2015, he ranked first. There is a large sample size of Realmuto's arm strength being among the best in baseball, if not the best.
Throwing out runners
"Pop time" is a crucial stat for catchers. It measures, in seconds, how quickly the catcher releases the ball on a stolen base attempt.
The MLB average pop time is 2.01 seconds.
In 2018, Realmuto had the best pop time in baseball: 1.90 seconds.
Alfaro ranked third at 1.94.
In 2016 and 2017, Realmuto ranked second-best in pop time with the same mark of 1.90 seconds.
Realmuto's exchange — how quickly the ball transfers from his mitt to his throwing arm on a stolen base attempt — is also among the best in baseball. The MLB average time hovers around 0.85 seconds. Realmuto ranked fourth at 0.68 seconds; Alfaro was 17th at 0.73 seconds.
Realmuto has graded out as MLB's fastest catcher four years in a row.
The MLB average sprint speed on a competitive play is 27 feet per second. Among catchers, who are obviously slower, it's 25 feet per second.
Realmuto has been between 28.6 and 28.8 feet per second every year since 2015.
Offensively, you don't need to dig too deep to see why Realmuto is an elite option.
Over the last three seasons, despite playing in a gigantic, pitcher-friendly ballpark and with little lineup protection around him, Realmuto hit .286/.338/.454.
He had a .792 OPS. The MLB average OPS for catchers during the same time frame was .699.
Realmuto's batting average was 57 points higher than the average catcher.
His OBP was 30 points higher.
His slugging percentage was 63 points higher.
Where Alfaro had the edge
The only category in which Alfaro was superior to Realmuto in 2018 was with pitch-framing. Alfaro graded out as a top-five pitch-framer. However, Alfaro's focus on catching the ball perfectly prevented him from catching it cleanly many times. That was the trade-off.
The Phillies worked tirelessly to develop Alfaro into an upper echelon pitch-framer. They should be able to do something similar with Realmuto, who doesn't lack any of Alfaro's tools.
If Realmuto's pitch-framing improves in 2019, the gap between he and Alfaro could grow from about a 2.5-win difference to closer to 4.0 wins.
For a team in the Phillies' position, a team on the precipice of contention, every additional win carries great importance.
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