Black, 25, has appeared in three games for the Pirates this season and has allowed two runs and six hits in four innings.
Black was 5-3 with 17 saves and a 2.51 ERA in 53 games with Triple-A Indianapolis this season. He allowed 28 hits, issued 21 walks and struck out 63 while holding opponents to a .169 batting average against.
Black was the 16th best prospect in the Pirates minor league system, according to MLB.com.
"His fastball can be plus, into the mid-90s with sink, and he combines it with a hard slider that could be a Major League average pitch," Jonathan Mayo of MLB.com writes about Black
According to Adam Rubin of ESPN New York, Black will not report to the Mets until rosters expand on September 1 - the 40-man roster currently stands at 38.
The Pirates were looking to call him up to help the team in September. Pittsburgh has told people he could evolve in to a closer, since he routinely hits the upper 90s with his fastball. He’s also 25 and still in Triple-A, but that’s mostly because he was converted to a reliever from a starting pitcher, after struggling with injuries and command of his off-speed pitches.
The Mets have some options with the 40-man roster when they add Black on Sunday. They can move Jeremy Hefner, Matt Harvey, Jenrry Mejia and possibly both Josh Edgin and Bobby Parnell to the 60-day disabled list which would free up an array of roster spots. That will allow them to not only add Black, but also guys like Juan Centeno, Tim Byrdak, and others they choose to evaluate over the final month of the season.