Raiders safety Lonnie Johnson Jr. broke his right leg in Las Vegas' mock game on Saturday, a person with knowledge of the injury told The Associated Press.

Lonnie Johnson Jr., who appeared locked into a training camp battle with Jamal Adams for a starting role with Las Vegas, collided with stud defensive end Maxx Crosby and broke his fibula on Saturday, according to ESPN. The injury will end Johnson’s season before it began.

Though the Raiders could be tempted to move Adams back to safety following Johnson's injury, it would be a bad idea. Firstly, Adams is thriving at linebacker, and defensive coordinator Patrick Graham has been pleased with his acclimation. Secondly, the aging defender no longer possesses the athleticism required to play a coverage role at safety.