GREEN BAY, Wis. -- The son of a former Green Bay Packer says he is heartbroken after losing his father's Super Bowl II ring, and he is offering a $5,000 reward for its return.

Mike Kostelnik told the Green Bay Press-Gazette that he believes he lost the ring that belonged to his dad, former Packers defensive tackle Ron Kostelnik, last weekend when he and his family went to visit his daughter at Indiana University and take another daughter to tour Miami University in Ohio.

He said he had been wearing the ring but took it off and stored it in the car's console.

Kostelnik said he made only one stop along the way, at a BP gas station in Greensburg, Indiana. When he was at Miami and discovered the ring was no longer in the console, the family went back to the gas station to look for it and to report it missing to police. It's possible the ring ended up on the floor of the car and was kicked outside the vehicle, he said.

"All I can do now is sit back and wait," Kostelnik said. "Maybe another idea will pop up, and I will follow all pursuits. Right now, I'm just waiting."

Ron Kostelnik played for the Packers for eight seasons from 1961 to 1968 and helped the team win five NFL championships and the first two Super Bowls. He finished his career playing one season for the Baltimore Colts in 1969 and was inducted into the Packers Hall of Fame in 1989. He died of a heart attack in 1993 at age 53.

"It's the ring my father wore," Mike Kostelnik said. "A lot of things he went through in life after football were in that ring. It's a ring that I wore during the times I was building my business. So, it's all of the energy and the issues that appear that are in that ring. I felt like it gave me a lot of strength in some very trying times."