NEW YORK -- The Mets left one of their top defensive prospects exposed to the Rule 5 Draft on Tuesday, as they did not make any 40-man roster adds prior to the deadline.

The team chose not to protect outfielder Jake Mangum, who is eligible for the Rule 5 Draft for the first time. Mangum, the club¡¯s fourth-round selection in the 2019 MLB Draft, was limited to 72 games this season due to a stress reaction in his spine. He is considered old for a prospect at 26 years old and does not rank among MLB Pipeline¡¯s Top 30 Mets prospects. But he is widely considered one of the organization¡¯s best defensive players at any position, which could entice rival teams.

The Rule 5 Draft is scheduled for Dec. 7 at the Winter Meetings in San Diego. Players who signed their first professional contract at age 18 or younger must be added to 40-man rosters within five seasons or they become eligible to be drafted by other organizations through the Rule 5 process. Players signed at 19 or older must be protected within four seasons. Clubs pay $100,000 to select a player in the Major League phase of the Rule 5 Draft. If that player doesn¡¯t stay on the 25-man roster for the full season, he must be offered back to his former team for $50,000.

? Toughest decisions for each team ahead of Rule 5 Draft

The Mets already had added three of the players they were likely to protect: third baseman Brett Baty, catcher?Francisco ?lvarez and pitcher Bryce Montes de Oca, all of whom made the roster in the second half of the season. That left a relatively shallow pool for the team to consider, including Mangum, outfielder Stanley Consuegra and right-hander Dedniel Núñez.

Although Consuegra -- ranked as the Mets' No. 23 prospect by MLB Pipeline -- is higher rated than Mangum, he is 22 years old with no experience above Class A ball, which makes him less likely to be drafted. Mangum, by contrast, is a former Mississippi State star who has played in 144 games in the upper Minors. Should he go unclaimed in the Rule 5 Draft, Mangum would have a strong chance to make New York¡¯s Opening Day roster as a reserve outfielder. But another team could take a chance on Mangum, a dynamic center fielder who holds MSU¡¯s career hits record.

The Mets have eight openings on their 40-man roster, but they will need to use several of those on pitchers to fill out their staff.