Merril Hoge understands Jahvid Best's frustration. He also understands the headaches, dizziness, wooziness and memory trouble Best has experienced at various points during his concussion-marred career.

Hoge was forced to retire in 1994 after his fourth concussion -- and second in a five-week span -- sent him into cardiac arrest in the Chicago Bears' lockeroom. He spent several days in intensive care and had to learn to read again.

"The fog didn't lift for 18 months,'' he said.

Best has also had four concussions: Two at Cal in 2009 and two with the Detroit Lions in 2011. He hasn't played in 18 months and failed a neurological test last fall.

The 24-year-old's career appears over.

"Based on the length of time, I don't know what doctor is going to clear him," Hoge said. "The longer symptoms linger, the more severe the trauma has been.

"To me, when it gets to this point, it's not even player's choice. The medical staff is not going to clear him. I don't know who clears him."

Best, who remains under contract with the Lions, wants to play again and works out in case he receives medical clearance.

One teammate, receiver Nate Burleson, urged him to retire. Hoge wasn't quite that explicit when asked about Best's future.

"He's just starting out," Hoge said. "You've worked so hard for so long -- for it to be over, that's tough.

"To make the choice you have to be well-informed. If you have aspirations to be a success long term, then you realize that if there are extreme brain issues, you just can't keep doing it.''