"After a long evaluation during spring training, after consulting with [manager] Terry [Collins] and the coaching staff, I made a recommendation to ownership in the best interest of the organization and Louie that he be released," general manager Sandy Alderson said. "Ownership approved."
"I feel calm and confident that I will be in a major league roster by Opening Day," Castillo told ESPNdeportes.com.
"Despite all the negative atmosphere of recent days, I'm positive and in the best shape for a long time," Castillo added. The Dominican was batting .283 in 28 at-bats in spring training at the moment of his exit from the Mets.
"I enjoyed every moment in New York and will always be grateful to the Mets. I have nothing negative to say about the organization," he said. "Baseball is a business. It is what it is."
Alderson refused to handicap the remaining field of candidates, but Rule 5 pick Brad Emaus appears a leading candidate. He has a supporter in J.P. Ricciardi, who was the general manager who drafted Emaus with the Toronto Blue Jays, and has a track record of walking more than striking out while displaying power that is in line with the Mets front office's philosophy.
Another candidate, Daniel Murphy, is expected to be on the team in some capacity because he would be an asset as a left-handed bat for the bench.
Justin Turner may have had the best spring, but he has minor league options remaining, putting him at a disadvantage.
Team sources say the final remaining candidate, Luis Hernandez, is only on the "outside" of the race.
"In spite of the fact no one has obviously separated himself in the competition, I think we have a good-enough sense of where this is going that we want to accelerate the process," Alderson said. "So it was important to scale the competition back a little bit."
Castillo had been a focal point of fan distaste with the Mets, along with left-hander Oliver Perez, who remains with the club for now. Castillo's production has slipped, and he also had a high-profile dropped popup at Yankee Stadium two seasons ago that turned an all-but-certain Mets win into a Yankees victory. Castillo was booed -- a rarity in spring training -- this week after he was slow to cover first base during an exhibition game.
"I don't think there's any question that there's some linkage between his situation and a perception of the Mets that has existed to this point," Alderson said. "That's something that was taken into account. At some point, you have to make an organizational decision that goes beyond just an ability to play or not play. So those things are relevant. And you try not to make them so controlling that it dictates the final decision under any circumstances. Realistically, it's a factor."
Before departing the complex, Castillo told Newsday he didn't believe he got a fair shot.
"I said I came here to play and you didn't give me the chance," Castillo told the newspaper about what he said in the meeting. "You didn't use me."
He added: "I'm going to wait, go home and hope to catch on with another team."
After 1 p.m. Sunday, Castillo can sign with another team for the major league minimum salary of $414,000.
The 35-year-old Castillo hit .235 with no homers and 17 RBIs in 247 at-bats last season with the Mets, and had been overtaken by Ruben Tejada and Hernandez as the starting second baseman.
Castillo arrived in a July 30, 2007 trade with the Minnesota Twins and signed a four-year, $25 million contract the following offseason. He is a career .290 hitter with 370 steals in 15 seasons with the Marlins, Minnesota and the Mets. He stole 62 bases in 84 tries in 2000; he was 8-for-11 last year.
Perez, who is now auditioning for a lefty specialist role despite a $12 million salary, appears headed for the same fate. However, said Alderson: "I'm not here to comment on his situation. That has to stand on its own."
Adam Rubin covers the Mets for ESPNNewYork.com. Information from ESPNdeportes.com's Enrique Rojas and The Associated Press was used in this report.