Detroit Lions wide receiver Calvin Johnson (81) is introduced before an NFL football game against the Green Bay Packers in Detroit, Thursday, Nov. 24, 2011. (AP Photo/Rick Osentoski)

Detroit Lions wide receiver Calvin Johnson (81) runs after a catch against the Green Bay Packers in the second quarter of an NFL football game in Detroit, Thursday, Nov. 24, 2011. (AP Photo/Paul Sancya)

FILE - In this Nov. 24, 2011 file photo, Nickelback lead vocalist Chad Kroeger and his band perform during halftime at an NFL football game between the Detroit Lions and the Green Bay Packers in Detroit. A spokeswoman for pop singer Avril Lavigne confirmed a Tues., Aug. 21, 2012 report from People.com that Lavigne and Chad Kroeger were engaged earlier this month after a six-month courtship. (AP Photo/Rick Osentoski, file)

In this Nov. 24, 2011, photo, Green Bay Packers fans cheer during warmups, at an NFL football game between the Packers and the Detroit Lions in Detroit. Lions defensive tackle Corey Williams used to get a kick out of seeing foam Cheeseheads scattered through the stands wherever the Packers played during his four seasons with Green Bay from 2004-07. Now he sees the green-and-gold army invade Ford Field every winter and braces for a hostile environment in what's supposed to be friendly territory. (AP Photo/Paul Sancya)