With any trade of this magnitude, the reaction is polarizing.
There's the portion of the fanbase that wants to push the chips in and try to win now with proven major-league talent. There's the other half that wants to hold onto top prospects, build a contender organically and maintain full use of its resources.
J.T. Realmuto is worth trading Sixto Sanchez. Realmuto is the best catcher in baseball and probably the only active catcher you could argue possesses all five tools. He can hit for average and power, field and throw well, and run the bases better than any everyday backstop.
You can't just look at Realmuto's production the last three seasons to form an opinion of what he's capable of producing offensively. Marlins Park is gigantic and suppresses extra-base hits. Last season alone, Realmuto had between 15 and 20 deep flyouts and lineouts that would have been extra-base hits at Citizens Bank Park.
Away from Marlins Park last season, Realmuto hit .283/.350/.520, numbers similar to guys like Francisco Lindor and Xander Bogaerts. There just aren't many, if any, catchers who give you that much on an everyday basis.
"But he's only under contract for two years"
Complete coverage of the Fightin' Phils and their MLB rivals from NBC Sports Philadelphia.
It's shocking how many people have used this as a reason not to make the trade. When did two years become two months?
Realmuto's under team control at discounted prices for the next two seasons. He'll make $5.9 million in 2019, and 2020 is his final arbitration year.
This is not some insignificant amount of time. It's two full years of the best catcher in baseball, in his prime, and in reality, it's probably more than that. The Phillies wouldn't make this trade with designs of letting Realmuto walk away easily after 2020.
"Is the upgrade at catcher worth it?"
Another common question from the anti-trade contingent. Realmuto is a sizable upgrade over Jorge Alfaro, an upgrade of between two to three wins and perhaps more, depending on how much Alfaro improves moving forward.
Alfaro showed some promising signs in 2018. His batting line was respectable for a catcher, and he did cut down on his strikeout rate as the season progressed. It would have been difficult for Alfaro to not cut down on his strikeout rate given that it was the highest K-rate in the National League in April. And in May. And in June. Second-worst in July. Third-worst in August.
Defensively, Alfaro has been praised by the Phillies and some of the fanbase for his pitch-framing acumen. He did grade out highly in pitch-framing metrics. However, calling his receiving subpar would be an understatement. Alfaro struggled to catch the ball in 2018, and it wasn't just blocking balls in the dirt. He also whiffed much more than usual on pitches off the outside corner, off the inside corner, high in the zone.
I've talked to quite a few people around the game, including some former players, who are astonished by the difference between the eye test of Alfaro's defense and what some of the metrics say.
This is where the bulk of the debate lies. Sixto Sanchez was regarded as the Phillies' top prospect and his was the name Phillies fans heard more than any other in recent years. Many did not see Realmuto as a meaningful enough upgrade to part with Sanchez.
If there was a high level of certainty that Sanchez's best-case scenario would play out in the years to come, trading Sanchez might have been unwise. But how confident can the Phillies be, right now, that Sanchez will grow into the top-of-the-rotation arm he has been billed as?
In 2018, Sanchez pitched 46⅔ innings. He's 20 years old and hasn't yet pitched at Double A. That's not his fault, the Phillies have been very protective with him.
But what would happen if Sanchez encountered elbow soreness again this season? It cost him the final three months in 2018 and a setback prevented him from pitching in the Arizona Fall League. If another injury occurs, his value will surely decrease. And then you're probably not getting a player as good as Realmuto with Sixto as the centerpiece.
"They should trade for a SP instead?"
OK, who? Who is this stud-level starting pitcher in his prime that is available? Right now, there is none. You could've gone after Corey Kluber, but he'll be 33 when the season starts and has a ton of mileage on his arm. You could've gotten Robbie Ray, but he's not nearly as much of a difference-maker as Realmuto.
Maybe the Phillies could've held on to Sixto and traded him for a starting pitcher ahead of the 2019 trade deadline. Or maybe they couldn't have. Realmuto was available right now. Do you hold out in hopes that maybe a starting pitcher more valuable than an elite, everyday catcher becomes available? You could have, but you might have been waiting a whole lot longer than a few months.
The Machado-Harper effect
If after acquiring Realmuto, the Phillies lose out on Manny Machado and Bryce Harper, they may still finish behind the Nationals in 2019. They would still have had one heck of an offseason, improving at catcher, shortstop, the corner outfield and bullpen, but it would feel incomplete without one of the superstars.
If the Phils can get Machado or Harper in addition to Realmuto, this might be the team to beat in the National League. It would be among the deepest lineups in all of baseball. With how few catchers can actually hit league-wide, there is unique value to having a catcher you can bat second, not eighth.
Think about this lineup for a minute ...
1. Jean Segura, SS
2. J.T. Realmuto, C
3. Manny Machado, 3B
4. Rhys Hoskins, 1B
5. Andrew McCutchen, LF
6. Odubel Herrera, CF
7. Nick Williams, RF
9. Cesar Hernandez, 2B
Insert mouth-wide-open emoji.
Click here to download the MyTeams App by NBC Sports! Receive comprehensive coverage of your teams and stream the Flyers, Sixers and Phillies games easily on your device.
More on the Phillies
It's been a good winter for the Phillies - and it can still get better
Done deal: Phillies land elite catcher Realmuto in blockbuster trade
Countdown to Clearwater: 5 questions about Phillies pitchers
Countdown to Clearwater: 5 questions about Phillies position players