(WNFL) - The Green Bay Packers will start practicing today for their Sunday home contest against Philadelphia. Coach Mike McCarthy says he'll proceed with the assumption that Seneca Wallace will be the starting quarterback in place of Aaron Rodgers, who's expected to miss around three weeks with his broken collarbone. The absence of the 2011 league M-V-P will put a burden on both the Green Bay offense and defense, and not just emotionally. The differences on offense appear obvious. On Monday night against Chicago, Wallace did not seem to have the throwing strength of Rodgers, as the backup played his first N-F-L game in a season-and-a-half. The Packers only converted 1-of-9 third down chances, forcing the defense to spend a lot more time on the field -- 33 minutes against to Chicago, compared to a low 19 minutes the previous weekend at Minnesota. The Bears especially wore down the Green Bay defense on an 18-play, 80-yard drive which left less than a minute for the Packers to pull off a miracle finish that never happened. The defense expects a big boost this week, when Clay Matthews returns from a broken thumb. He's expected to return to practice today, and play on Sunday wearing a protective club.