This story was excerpted from Anthony DiComo’s Mets Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

Toward the end of a frustrating first inning for Tylor Megill last Saturday at Citi Field, Megill managed to prevent significant damage by stealing a few strikes.

Turns out he had a secret weapon. As Megill struggled to find the strike zone, catcher Francisco Álvarez darted his mitt across the zone on anything close, notably grabbing two outside fastballs to Elias Díaz and pulling them back toward the middle of the plate. Both, by the letter of the law, were balls -- so much so that Díaz began arguing with home-plate umpire Alex MacKay during the at-bat, gesturing with his arm to indicate he was well aware of Álvarez’s tricks.

This is becoming Álvarez’s reputation and, for the Mets, it’s a very good thing. The rookie catcher -- oft criticized as a prospect for his defensive rawness -- is rapidly developing into one of the best pitch framers in baseball. About five weeks through the season, Álvarez briefly rated as high as the 96th percentile of Statcast’s framing metric, converting more pitches in the so-called “Shadow Zone” into strikes than all but three big league catchers.

“We’re excited about where he’s at,” said catching instructor Glenn Sherlock. “But he wants to be better. He’s working very hard.”

During Spring Training, Álvarez performed framing drills most mornings, working alongside Tomás Nido-- another of the league’s top framers -- and Omar Narváez. Sherlock supervised, and Álvarez credited another Mets coach -- Minor League catching instructor Hector Alvarez -- as being instrumental in his defensive development. The key, the younger Álvarez says, is patience: waiting until the last possible moment to reach out and grab a pitch, instead of succumbing to the temptation to catch it fractions of a second earlier.

By the time Álvarez debuted last season, his framing had improved enough to be considered one of his relative defensive strengths, but Mets officials still worried how he would adapt to catching a staff full of veterans. Even today, as Sherlock noted, Álvarez is not a finished product. But he’s light years ahead of where he was as a teenager.

“It’s been super, super important for me since I’ve been up here to have a lot of success in that regard,” Álvarez said through an interpreter.

Álvarez feels most comfortable framing pitches near the bottom of the zone, which pitcher Max Scherzer said is natural for a player of his stature; Álvarez is listed at 5-foot-10, tied for the shortest player on New York’s roster. His skill has already allowed him to vault ahead of Nido on the depth chart, and it should help him stay in the big leagues while the Mets wait for his plus-plus raw power to translate more fully into Major League games.

“Defense is super important,” Álvarez said. “That’s the cornerstone of the defense, really, is a good defensive catcher. That’s why it’s so important and such a big thing for me to focus on.”