49ers not missing much with Cox at CB

SANTA CLARA, Calif. -- Perrish Cox was supposed to be the San Francisco 49ers' nickel cornerback, covering slot receivers in the inside. But when starting cornerback Tramaine Brock went down with a toe injury in the season opener at the Dallas Cowboys, Cox was pressed into service.

Neither he nor the Niners have missed a beat.

Because while Brock began rehabbing on a side field Wednesday, Cox has established himself on the outside. His two interceptions are one off the league lead and his eight passes defensed are the most in the NFL.

Surprised much? Niners coach Jim Harbaugh is not.

"We thought Perrish coming into the season had tremendous value to our football team," Harbaugh said. "(I) like the way he's playing, very much so. It bodes well for our football team."

Oh yeah, and Cox has also recovered a pair of fumbles and has 10 tackles. Not bad for a guy who was supposed to be a mere specialist, no?

And yet, Cox said he's still up to speed on playing inside for the time when Brock returns.

"Oh yeah, when I go in for dime (packages), same thing," Cox said. "Dime, the nickel, you know, safety and everything. I know it all, so I pay attention and keep taking notes on all that."

And with former 49ers quarterback Alex Smith leading the Kansas City Chiefs into Levi's Stadium this weekend, you'd think Smith would have an inkling as to the Niners' defensive tendencies. Cox smiled.

"He don't know much," Cox said. "We change everything up and regardless what he does know, he's still got to come out here and play ball."

Cox has obviously already been doing that for the 49ers.