Alvarez will join the Mets' big-league roster Friday, Joel Sherman of the New York Post reports.
The Mets are in the thick of a tight race for the NL East crown despite a major weakness at the catcher position. James McCann owns a .519 OPS on the season, while Tomas Nido's .598 OPS isn't much better. Exactly what kind of boost the 20-year-old Alvarez can provide right away is unclear, though he's one of the highest-rated catching prospects in the league and has hit .260/.374/.511 with 28 homers in 112 games across the two highest levels of the minors this season, so he certainly has the potential to make an impact.