NEW YORK -- A year ago, the Mets left outfield prospect Wuilmer Becerra -- part of the 2012 trade that brought Noah Syndergaard and Travis d'Arnaud to New York for R.A. Dickey -- unprotected in advance of the Rule 5 Draft. No one selected him. But the Mets were not about to take that risk again.
The Mets on Friday added Becerra, No. 1 prospect Amed Rosario and three others to their 40-man roster, thereby protecting them from the Rule 5 Draft on Dec. 8.
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, 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.