Cobb isn't in line to play in Thursday's preseason contest at Kansas City, Mike Spofford and Wes Hodkiewicz of the Packers' official site report.
Cobb will be joined on the sidelines by fellow wide receivers Allen Lazard, Sammy Watkins and Christian Watson (knee), meaning Green Bay's top options at the position won't see game action until the team's season opener Sunday, Sept. 11 in Minnesota.