Phillies manager Rob Thomson called Mick Abel into his office Friday morning and let him know he was being optioned to triple-A Lehigh Valley. “I think he understood,” Thomson said. “And I think he’s going to go down there,

Walker will start Tuesday at San Francisco. He could pitch four innings or so. Then, during the All-Star break, the Phillies will reassess.

The Phillies have demoted rookie right-hander Mick Abel, who has struggled since he struck out nine in his major league debut, to Triple-A Lehigh Valley.