NEW YORK -- Neil Walker plans to undergo surgery to repair a herniated disk in his back, ending his season and potentially his New York Mets career.
Manager Terry Collins announced Walker's intention and said the second baseman would address the subject Thursday.
Walker has been nagged by recurring lower-back trouble, which has been causing weakness in a leg and numbness in a foot.
General manager Sandy Alderson earlier Wednesday expressed confidence Walker could play through the injury, but the parties subsequently had another doctor review Walker's MRI and the direction changed. Collins said the decision to have surgery surprised him.
"After all the evidence has been gathered, he thinks that's where he's probably headed," Collins said. "... All of the stuff that has to come together to reach a decision, for me it's mind-boggling -- all the different pieces that have to be put in place. He'll give you the whole diagram tomorrow, but we're certainly very disappointed that it comes to this. He's had a tremendous year for us. Certainly he makes the decision, and it's in his best interest."
Acquired from the Pittsburgh Pirates last December for left-hander Jonathon Niese, Walker hit .282 with a career-high-matching 23 homers and 55 RBIs in 412 at-bats.
Niese was reacquired from the Pirates on Aug. 1, but since has undergone surgery to repair a torn meniscus in his left knee that likely will end his season, too. Walker's loss means three-quarters of the Mets' Opening Day infield is done for the season. Third baseman David Wright underwent surgery to repair a ruptured disk in his neck, while first baseman Lucas Duda has suffered a setback in his attempt to return from a stress fracture in his lower back.
Walker is eligible for free agency this winter. It remains to be seen how much the 30-year-old Walker's value will be affected by the back surgery. It's also uncertain whether the injury diminishes the Mets' interest in Walker. Alderson recently had expressed an interest in engaging Walker's agent about a potential extension.
The Mets have several options to cover Walker's absence. Wilmer Flores and Kelly Johnson, who combined for five RBIs in Wednesday's 5-2 win against the Miami Marlins, likely will share the position. The Mets also figure to promote infielders T.J. Rivera and Matt Reynolds from Triple-A Las Vegas when the Pacific Coast League regular season ends on Monday.
The Mets did make a move Wednesday to shore up their late-inning relief. They acquired right-handed reliever Fernando Salas from the Los Angeles Angels for minor-league right-hander Erik Manoah. Because Salas was acquired before midnight, he will be eligible for the Mets' postseason roster.
Salas, 31, was 3-6 with a 4.47 ERA and six saves in 58 relief appearances with the Angels this season. He is eligible for free agency this offseason. The Mets also sent Triple-A catcher Nevin Ashley to the Texas Rangers for cash.
Mets 2B Neil Walker will undergo back surgery, ending season