News and notes from Wednesday in 49erland

    Of course, Joe Staley (knee), Nate Clements (shoulder) and Demetric Evans (shoulder) are out with injuries. Jean-Francois will be the 49ers' fifth defensive lineman, while Patrick will take over as the team's backup at both left and right tackle spots.   Barry Sims was the 49ers' backup tackle, but he will now start at left tackle in place of Staley. Tony Wragge will remain as the team's backup at center and the two guard positions.   * * *   Coach Mike Singletary said he there's a chance the team will get the services of safety Reggie Smith this week. Smith has been out since Sept. 27 with a severely strained groin.   * * *   Why has Vernon Davis' game taken off this season? Well, he credited the fact that he's around Mike Singletary, of course. But the first explanation he gave was "opportunity."   Under Mike Martz there would be games in which Davis was kept in to block on more than 50 percent of the team's...