49ers sign CBs Shareece Wright, Chris Cook

Perrish Cox led the San Francisco 49ers with five interceptions last season while Chris Culliver had four picks. The two cornerbacks will ply their trades as free agents next year for the Tennessee Titans and Washington, respectively.

The Niners, meanwhile, announced Saturday the signing of a pair of corners in Shareece Wright, a free agent who started his last 27 games for the San Diego Chargers, and Chris Cook, who played six games for the 49ers last year before his season ended with a torn hamstring.

But while Cox and Culliver combined for nine picks in 2014, Wright and Cook have a combined … wait for it … one interception. In a combined 84 games. In a combined 56 starts.

Something seems off kilter, no?

Especially when you look at the numbers crunched by Pro Football Focus.

It’s already been established that Wright is a pass interference magnet, the eight interference flags thrown at him last year -- one was declined -- led the league, one ahead of such notables as Buster Skrine and Blidi Wreh-Wilson, per ESPN Stats & Info. And Wright’s 12 pass interference penalties called since 2013 are the most in the NFL.

But PFF also reported that “Wright ranked in the bottom 10 among CBs in both years as a starter” for the Chargers with a minus-16.4 coverage grade last season, minus-11.1 in 2013.

Wright, who is not necessarily a big DB at 5-foot-11, 182 pounds, played “out wide roughly 93 percent of the time the last two seasons” when lined up over a receiver, PFF found.

And while Cook had what PFF described as a “great” preseason last year after coming to Santa Clara following four seasons with the Minnesota Vikings, allowing one catch in nine targets for six yards with two INTs for a 0.0 passer rating against in 36 coverage snaps, it came in, well, the preseason.

But at 6-2, 200 pounds, Cook is a more physical presence at corner.

Still, despite the acquisition of Wright and the re-signing of Cook, neither figure to start. At least, not on March 14. At the moment, the starters would seem to be five-year veteran Tramaine Brock and second-year man Dontae Johnson.

Brock and Johnson, at least, have eight total INTs, with seven by Brock, in six combined seasons.