MLB requires teams to add players who signed at age 18 or younger to 40-man rosters within five professional seasons, or those who signed at 19 or older within four seasons, or they will become eligible for other organizations to draft. Clubs pay $50,000 to select a player in the Major League phase of the Rule 5 Draft, slated for Dec. 8. 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 $25,000.

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In addition to Rosario and Becerra, the Mets added catcher Tomas Nido, and right-handers Marcos Molina and Chris Flexen. Those left unprotected include reliever Paul Sewald, who struck out 11 batters per nine innings at Triple-A Las Vegas last year; defensive-minded outfielder Champ Stuart; and breakout infielder Phillip Evans.

Rosario, 20, hit .324 over two levels this season, climbing as high as Double-A Binghamton and appearing in the Futures Game. He is the Mets’ shortstop of the future, perhaps ready to take over the full-time job as soon as 2018.

Becerra, 22, played only half a season before undergoing season-ending shoulder surgery in July. Though the Mets’ No. 7 prospect was productive before his injury, batting .312 in 65 games for Class A St. Lucie, he hit just one home run.

Molina on work ethic, excitement

Molina on work ethic, excitement

Molina discusses his Fall League experience

Mets prospect Marcos Molina talks about working hard and his excitement to be at the Arizona Fall League

Molina, 21, and Flexen, 22, are both former Tommy John patients with opposing profiles. The former is a hard thrower whose fastball reached the mid-90s before surgery, which knocked him out for all of last season. The latter is a strike-thrower who tops out in the low 90s. They are the Mets’ 11th- and 29th-ranked prospects, respectively.

Nido, 22, clocks in as the Mets’ 21st-ranked prospect after taking significant strides forward this year at St. Lucie. The catcher hit .320 with seven home runs in 90 games, making him an intriguing prospect for a Mets team with an uncertain future catching situation.

Though it is often difficult to handicap the Rule 5 Draft, the unprotected player who may entice rival teams the most is Sewald, a 26-year-old who posted a 1.85 ERA in 24 1/3 innings after the All-Star break. Teams tend to be more willing to gamble a roster spot on a live arm like Sewald, versus a position player such as Stuart or Evans.

But the Mets only had so much room to protect players, as their 40-man roster is full.

Anthony DiComo has covered the Mets for since 2008. Follow him on Twitter @AnthonyDiComo and Facebook, and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.

Source: Mets News / Becerra, Rosario among Mets’ protected prospects