The New York Mets said ace pitcher Johan Santana was placed on the 15-day disabled list Saturday due to a sprained right ankle. Santana (6-7) apparently suffered the injury July 6 and had struggled ever since, including a three-inning start against the Dodgers Friday in which he allowed six runs on seven hits. In his last three starts, Santana gave up 19 runs on 28 hits in 12 2/3 innings. The Mets called up pitcher Jeremy Hefner from triple-A Buffalo to fill Santana\'s slot on the roster