NEW YORK—Like Mark Teixeira before him, Alex Rodriguez has gone from puzzlingly cold to exceptionally hot in a flash. And with him have gone the Yankees. In such a funk as they slogged through the Interleague portion of their schedule, the Yankees won their last two games in Atlanta and have been soaring since. They are now winning games—and quite a lot of them—with both efficiency and precision. The latest example came on Wednesday at Yankee Stadium, when Andy Pettitte th...