New York Mets pitcher Taijuan Walker has been scratched from Sunday's start because of a bulging disk, manager Buck Showalter said Saturday.

The Mets have not yet named a replacement for Sunday's game against Philadelphia.

Walker (10-3, 3.36 ERA) lasted only two-plus innings in Tuesday's loss to Atlanta, leaving with back spasms. He was visibly wincing after running to cover first base on a ground ball and said after the game that his back "started getting tight" as he walked back to the dugout.

Showalter said Walker possibly could return to the rotation against the Yankees on Tuesday.

The Mets enter play Saturday with a 3½ game lead over the Braves in the NL East.