Dodgers first baseman James Loney is having an MRI on his left knee after experiencing stiffness following Friday night’s game, manager Don Mattingly said Saturday. Loney first felt discomfort Thursday while stretching, Mattingly said, but added that the injury is believed “minor because he “has no pain.” “It seems minor, he played last night and had no pain,” Mattingly said. “He knows his body. It’s precautionary, so he knows how to deal with it. Once you know what it is, you can strengthen other areas.” Loney had knee issues in high school, but nothing to impact playing time since the Dodgers drafted him in the first round of 2002. — Ken Gurnick