Mike McCarthy announced today that Evan Dietrich-Smith will start at center for the Packers against the Tennessee Titans.   Veteran Jeff Saturday has snapped all 14 games but did not have a full week of practice this week.  He's been limited most of the week with neck and shoulder issues.  Saturday is officially listed as probable, and may still see action so the move may be more of a peek into the future and a chance to see how Dietrich-Smith will fare at arguably his better position in a regular season game.   Evan started a couple of weeks at guard when T.J. Lang battled through an ankle sprain, he was awareded the game ball on offense for his work against the Detroit Lions at Ford Field last month.  Lang, meanwhile, has been cleared from his concussion suffered last week in Chicago and will work at left guard with rookie Don Barclay continuing at right tackle.  Both Saturday and Dietrich-Smith seemed a bit surprised at the timing of the change but added they'll accept the coach's decision in whatever he thinks is best for the team.   The Packers are 13 point favorites against the 5-9 Titans.   Five players have been ruled out of the game.  Tom Crabtree is a scratch with a hamstring injury and the rest have missed several games including Jordy Nelson (hamstring), C.J. Wilson (knee), James Starks (knee) and Charles Woodson (collarbone).   Woodson had a personal matter to attend to and wasn't at practice Thursday, the storm left him with travel issues and he was back in the locker room this afternoon.   Woodson has been working the past couple of weeks and is anxious to return but that may come in the regular season finale indoors at Minnesota.  Woodson doesn't think the layoff will hurt his game, saying he hasn't forgotten how to play the game.  The rest of the final injury report for the Packers has three players listed as questionable, Greg Van Roten with a back issue,  Jerel Worthy with a hamstring and Alex Green with a concussion.  While Lang has been cleared, Green has not.  McCarthy said a final test will be conducted on Saturday but he's expecting Green to pass and get the OK to play. Erik Walden with an ankle injury, Randall Cobb with a sore shoulder and Aaron Rodgers with an ankle were all full participants at Friday's practice and are listed as probable for Sunday's game.