Walker (foot) will throw a light bullpen session Sunday, Alex Coffey of The Philadelphia Inquirer reports.
Walker was forced out of his last start Thursday versus the Mets after taking a comebacker off his left foot. Once he gets a chance to throw off a mound Sunday, the Phillies will make a decision on whether or not the 31-year-old righty will make his next scheduled start -- tentatively scheduled for Wednesday against the Rangers. If the Phillies deem Walker unfit to start, Spencer Turnbull would return to the rotation.