The Packers today placed running back Cedric Benson on injured reserve with the new designation that would allow the team to bring him back onto the active roster.  Benson suffered a Lisfranc injury to his foot in the second quarter against Indianapolis. The sprain is where the five metatarsal bones converge above the arch of the foot and takes anywhere from six to eight weeks to heal.   Head Coach Mike McCarthy said Benson will be allowed to return to practice after six weeks, about the end of November, and the team will have another 2 weeks to either re-activate him or keep him on IR for the remainder of the season.  The roster rule change was implemented this year by the league.  Previously, any player placed on injured reserve would not be allowed to come back. McCarthy said Alex Green will get the first shot at Benson's lead back role.  Green carried the ball 9 times for 55 yards against the Colts but did not look very impressive until breaking a 41 yard dash late in the game.   James Starks has recovered from a turf toe injury and began practicing two weeks ago but was a healthy scratch last week.   Second year pro Brandon Saine will also get an opportunity to earn snaps during the practice week.  Three other starters did not practice today as the team began preparations for the undefeated Houston Texans.  Jermichael Finley sat out with a shoulder injury also suffered against the Colts.  In the locker room after practice, Finley said, "If it was my call, I'll play."  Greg Jennings also did not work, still recovering from a lingering groin injury that has forced him to miss two games this season.  McCarthy said they'll take to the end of the week before determining if the Pro Bowl receiver will return in Houston Sunday night.  Defensive tackle B.J. Raji also missed practice because of a sprained ankle that knocked him out of the Indianapolis game.  Raji will continue wearing a protective boot and he indicated it will be a day by day process.  Nick Perry had to break out the checkbook this week.  The number one pick admitted he was fined by the league for his big hit on Andrew Luck which drew a 15 yard penalty.  Perry was told by the league he led with the crown of his helmet which warranted the fine.  Luck fumbled on the play and appeared dazed when Perry slammed into his upper chest.  Perry said the discipline won't change his aggressiveness but he'll be more cognizant of his technique.