NEW YORK -- About 16 miles south of Citi Field, the Mets on Monday opened their MCU Park alternate training site in Brooklyn, where prospects not ticketed for the Opening Day roster -- but with a chance to make the team at some point this season -- will train.

In a related move, the Mets added seven players to their 60-man pool: right-handers Matt Blackham, Jordan Humphreys and Franklyn Kilomé, lefties Stephen Gonsalves and Thomas Szapucki, infielder Jake Hager and catcher David Rodríguez. That brings their total pool size to 58, with two slots remaining to add players from inside or outside their organization. Among the long-shot possibilities is outfielder Tim Tebow, whom general manager Brodie Van Wagenen mentioned as a consideration earlier this month.

The team plans to send additional players from Citi Field to Brooklyn by Tuesday as it pares down its roster in preparation for Opening Day. Teams are allowed only 30 players on their Opening Day roster, plus a three-man taxi squad to give them flexibility in the event of injuries or illness. The 30-man rosters will be reduced to 28 players two weeks after Opening Day, then to 26 players two weeks after that. (The three-man taxi squads will remain throughout.)

The point of the 60-man player pool is to earmark which players are eligible to perform over the course of the season. While the Mets can add to their pool after Opening Day, they won’t be able to do so without removing someone else. In many cases, that would mean releasing or waiving players, thereby making them ineligible to return for the rest of the season.

Given such strict rules, a Mets team with designs on competing for a title figures to fill out its Opening Day roster mostly with veterans. The seven prospects the team added on Monday will provide a measure of depth, while also offering those players an opportunity to train in the absence of Minor League Baseball.

Szapucki, Kilomé and Humphreys -- the Mets’ seventh-, 12th- and 14th-ranked prospects -- have all spent portions of the past two years rehabbing from Tommy John surgery. That trio sits behind David Peterson, Walker Lockett and Corey Oswalt on the club’s starting pitching depth chart, but one or more of them could contribute late in the year. So could Gonsalves, an offseason waiver claim who stretched out as a starter this spring.

More likely to contribute imminently may be Blackham, a hard-throwing right-hander who struck out 70 batters in 55 1/3 Minor League innings in 2019, reaching Triple-A Syracuse in the process.

Hager and Rodríguez were Minor League signings over the winter who offer the Mets depth in the infield and at catcher, respectively.