Tramaine Brock: I've always wanted to play in the slot

SANTA CLARA, Cailf. -- The general feeling goes something like this: if you’re the nickel cornerback, you’re only the third-best cornerback on the team.

Tramaine Brock, though, is putting that theory to rest. Because not only is Brock the most seasoned and successful cornerback on the San Francisco 49ers roster, he also wants to slide inside when the 49ers go into the nickel.

"I’ve always wanted to play it, but the defensive coordinators in the past didn’t want me in the slot," Brock said Thursday. "They wanted other guys there, so I never got a chance or opportunity.

"Now, they’ve given me the opportunity to play it. I want to start."

Rookie coach Jim Tomsula is impressed by Brock’s desire.

"How many starting corners come to you and say, 'Hey, give me a shot at that nickel?'" Tomsula said. "They just want to stay out there and do their thing."

Then what makes the 5-foot-10, 197-pound Brock so effective inside?

"Quite frankly, the foot quickness," Tomsula said. "You see it. He’s got that small-box quicks. Smooth athlete (who) can run, but he can change direction. He can plant and drive.

"Start looking at some of those slot posiions and those are those little jitterbug dudes. And with his skill set, he’s bright and he gets it. And he’s a competitive son of a gun."

Thus far in camp, whenever Brock goes inside, Dontae Johnson comes takes Brock’s spot, with Shareece Wright staying out at the other cornerback position.

Brock’s desire to play the nickel came to fruition because Jimmie Ward, the 49ers’ first-round draft pick in 2014, is still rehabbing from his broken foot suffered last season. Otherwise, Ward was penciled in as the starting nickelback.

And the team releasing veteran cornerback Chris Cook last week sent a message to the corners.

"No 1, it tells us that they’re definitely looking for younger guys to step up and be a part of the defense," said Keith Reaser. "And then it also tells you, too, 'Hey, if I’m not getting it done or whatever, I could be gone as well.'"

Brock has seven career interceptions. The other five corners have two picks ... total.

And after an injury-plagued season last year -- Brock was a starter but injured a toe in the opener at Dallas after nursing an inkle injury, and then tweaked a hamstring, limiting him to just three games -- it took until the start of training camp two weeks ago for him to feel completely healthy again.

And he has yet to take a "vet’s day off" in camp. Feeling whole has allowed Brock to jump at the chance to play the slot.

"I can be aggressive," he said. "We’ve got a few blitzes from the nickel, man-to-man. It’s just, it’s a challenge.

"I would say it’s harder. It’s more space so you’ve got a lot of ground to cover so, I mean, it’s a little bit harder than the outside corner."