Giants activate Casey Schmitt, DFA David Villar

The San Francisco Giants are rolling, having just swept their former cross-town rivals, the Athletics, in an exciting weekend series. But the old phrase “if it ain’t broke, don’t fix it” is clearly not one that Buster Posey prescribes to. Because, ahead of their series opener on Monday against the Kansas City Royals, the Giants made a move at first base and designated hitter, swapping in Casey Schmitt at the expense of David Villar.

San Francisco made the move primarily because Schmitt, who broke camp on the roster, is healthy again. Schmitt suffered an oblique strain in the batting cage before a game a month ago, and hasn’t played since April 17. He began a rehab assignment with AAA…