Raiders rookie inside linebacker Cory James, the “next man up,” knows that the Titans are going to be running right at him Sunday in Nashville. James will be taking a lot of snaps from Ben Heeney, who struggled covering running backs and tight ends in Sunday’s loss to the Falcons and “left the door open” for James, according to head coach Jack Del Rio. Heeney, who coaches and teammates spoke so highly of in training camp, had the green dot (helmet with a communication device) taken away before the season opener. [...] the Raiders looked so bad Sunday and are giving up a league-worst 8 yards a play. Del Rio said Heeney barely beat out James in training camp, and safety Keith McGill the same with rookie Karl Joseph, and now it’s time to turn things around. Del Rio said the sixth-round pick has been making plays at practice. At Colorado State, the 6-foot-1, 230-pounder moved from defensive end to outside linebacker to inside linebacker. Raiders cornerback David Amerson, who sustained a concussion late in Sunday’s loss, was unavailable to talk to reporters Tuesday as he is still going through the NFL’s protocol.