Walker was removed from Wednesday's game against the Astros due to an apparent left leg injury, Anthony DiComo of MLB.com reports.
Walker was struck by a Jeremy Pena comebacker while making a relief appearance in the bottom of the seventh inning Wednesday afternoon at Minute Maid Park. He had a noticeable limp as he made his way into the Mets' dugout but ultimately walked off under his own power. Consider him day-to-day for now.