The wide receiver has been taking part in daily workouts at the Packers' indoor training facility as he looks to increase his role in the team's offense.
The 22-year-old told the team's official website: "I just want to continue to improve, to get stronger, to get more powerful, to get more explosive and build myself up as a player, and build into a leadership role on this team.
"I want to do everything I can to put us in the best position for next season. It can get extensive at times. Earlier this week, we had some harder workouts."
Cobb had a break-out year with the Packers in 2012, scoring eight touchdowns for 954 receiving yards, while adding a further 964 yards with kick returns.