Coach Mike McCarthy says his newcomers will have to catch up quickly as the Green Bay Packers begin their training camp practices today (Thursday). He says that in his first season in 2006, it took 12 sessions to install the Packers’ basic schemes on offense, defense, and special teams. This year, it will be down to eight practices as McCarthy expects his players to hit the ground running after offseason workouts since May — and as the coach puts it, “The educational period is over.” Seventeen of last year’s 22 starters are back — but about one third of Green Bay’s 90 man roster is made up of rookies and first year players, and only 48 have at least two years of N-F-L experience. Defensive tackle Letroy Guion is expected to practice, as he faces a trial in Hawaii for a June 21st drunk driving arrest which followed the imposing of a four game N-F-L suspension at the start of the regular season for violating the league’s policy on performance enhancing drugs.