The Bills came into training camp set with Stevie Johnson as one of their starting receivers and little other certainty in the receiving corps so he’s not a player they want to see dealing with an injury. That’s where they find themselves as of Friday morning however. Chris Brown of the Bills website reports that Johnson pulled up in the middle of a route during practice and grabbed the back of his left leg. He left the field with the team’s training staff and coach Doug Marrone confirmed that Johnson has a a hamstring injury and will undergo further evaluation.