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.

Arm strength

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.