NEW YORK — Righthander Brad Peacock is no longer part of the Astros’ starting rotation and has been moved to the bullpen, manager Bo Porter said Monday. Peacock, 25, was named the Astros’ No. 4 starter toward the end of spring training, beating out Alex White for the spot. White recently underwent season-ending Tommy John surgery. Peacock is 1-3 this season with an 8.44 ERA. He allowed five runs and six hits in 3 1/3 innings Saturday during a loss to Boston. After the defeat, Porter said changes would be made to the team’s starting rotation if struggling pitchers such as Philip Humber, Erik Bedard and Peacock didn’t quickly improve. [...]