Smith fails to impress

Some people in the Raiders organization thought firstround pick Gareon Conley would push cornerback Sean Smith for a starting job this season. Friday’s training-camp practice in Napa was a big step in that direction, and Conley hasn’t even set foot on the field yet due to shin splints.

Smith was relegated to the second team in scrimmages, with TJ Carrie replacing him and lining up opposite David Amerson. When the offense went with three receivers, undrafted rookie corner Breon Borders came on and joined the starters.

The 6-foot-3 Smith is coming off a mediocre season after the Raiders signed him away from the Chiefs for four years and $38 million (he is guaranteed $20 million of that, but none in 2018). He had trouble with speedy receivers last season, starting off with the Saints’ Brandin Cooks, who beat him for a 98-yard touchdown in the opener.

Smith has not been sharp the first week of camp, and Friday he gave up a big play to Johnny Holton.

Quarterback Derek Carr, meanwhile, has been impressed with Borders, out of Duke.

“Every time I turn the film on it’s like he makes a play,” Carr said. “That’s how those guys catch your eye. When you’re an undrafted guy, it’s hard, because obviously you’re not going to have the first or second-team reps all the time. It turns into a, ‘Who’s 31?’ kind of a thing.

“He’s really proven himself.” Briefly: Raiders third-round pick Eddie Vanderdoes more than held his own against guard Gabe Jackson, as the defensive tackle would have had a sack Friday — if such things were allowed. … After missing a practice and then dominating Thursday’s, receiver Amari Cooper took Friday off with a minor injury. K.J. Brent, who was on the practice squad last season, continued to make tough inside catches in Cooper’s place. … Rookie safety Obi Melifonwu also didn’t participate. … After practice, a young fan held out a bag of Skittles candy and Marshawn Lynch got a running start, took the handoff and ran to the locker room.