South Korea outfielder Lee Jin-Young, left, congratulates infielder Jung-Ho Kang...

South Korea outfielder Lee Jin-Young, left, congratulates infielder Jung-Ho Kang in the eighth inning of their World Baseball Classic first round game at the Intercontinental Baseball Stadium in Taichung, Taiwan, March 5, 2013. Credit: AP / Wally Santana

Jung-Ho Kang was officially posted Monday afternoon, allowing major-league teams to submit blind bids to gain exclusive negotiating rights with the slugging shortstop from South Korea.

But despite the Mets' desire to upgrade at shortstop over Wilmer Flores, a source said they remain undecided about whether to bid on Kang, whose prodigious power comes with question marks.

Internally, sources said the Mets have not reached a consensus regarding Kang and whether his production will translate against better pitching in the U.S. And even among those who believe that it will, questions exist about whether he has enough range to stick at shortstop.

The Mets and other interested clubs will have until 5 p.m. Friday to submit blind bids to the Nexen Heroes, Kang's club in the Korean Baseball Organization. Should Nexen determine that the bid is high enough, the team that submitted it will be revealed and given a 30-day window to negotiate with Kang. But if a deal isn't reached, Kang's rights will remain with Nexen and the posting fee will be refunded. It's also possible that Kang's team in Korea will decide that the bid isn't high enough and simply dispense with the process.

Kang reportedly could fetch a posting fee in the range of $10 million to $15 million. He's also said to be shooting for a three-year deal worth about $24 million. Kang, 27, had a slash line of .356/.459/.739 with 40 homers and 117 RBIs in 117 games in the notoriously hitter-friendly KBO. "He hit a homer off me,'' said veteran big-league reliever Dana Eveland, who faced Kang while pitching in Korea in 2013. "He's a good bat and could be an average defender. He's a better player than people are giving him credit for.''

One talent evaluator questioned whether Kang's defense would represent an upgrade over that of Flores, whose lack of range has long been criticized. Offensively, Kang's leg kick also has some worried that he'll be vulnerable against big-league pitchers.

Still, Kang's power stands out. "I know KBO and MLB is different,'' said one evaluator who has scouted Korea. "But baseball is baseball.''

The Mets have been willing to explore an alternative to Flores, though their chances continue to dwindle. Another option came off the board Monday when the Astros signed Jed Lowrie to a three-year deal worth $23 million.

Mayberry signing official. The Mets officially announced the signing of outfielder John Mayberry Jr. to a one-year contract worth a guaranteed $1.45 million. The deal also includes a possible $500,000 in incentives based on plate appearances and awards, according to an industry source. To make room on the roster, righthanded reliever Gonzalez Germen was designated for assignment.

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