Damien Woody explains why he expects Kevin O'Connell to get the best out of J.J. McCarthy with the Vikings. (1:10)Open Extended ReactionsEAGAN, Minn. -- Minnesota Vikings receiver Justin Jefferson will miss some time during training camp because of a strained left hamstring, coach Kevin O'Connell said Friday. The Vikings sent him for an MRI after practice, and the test showed what O'Connell called a "very mild" strain. Jefferson was not going to participate in the Vikings' preseason games, regardless of his health, O'Connell said. Speaking Thursday after practice, Jefferson said: "With the past recent injuries and the stuff that I had gone through before, just taking precautions and understanding that it's the second day of camp -- not the thirtieth.