OXNARD, Calif. -- Marcus Spears is 29 and entering his eighth season in the NFL. He has been playing football for most of his life, and he knows there will come a day when he will not play again.

Spears has missed the last few days of training camp after suffering a hit that led to concussion-like symptoms. In recent years the NFL has adopted a stringent return-to-work policy with baseline testing, and Spears took the test Tuesday.

With an off day today, the hope is that he is close to returning to the field.

“In college I’d bang my head, get cross eyed and you shake your head and you’re back in the game,” Spears said. “As a player, you know something could be long term and something that gets you in trouble.”

Spears admits it is difficult at times to see former players handle life with debilitating injuries.

“I saw Earl Campbell before and I was like, 'Wow' with the way he struggled walking,” Spears said. “(Jack) Tatum from the Raiders, knee replacements and stuff like that. That’s the game we play. What has happened over the years, they have made it more of an issue. They’ve brought it up more so guys know what to do to prepare for that situation later. There’s so much you can do for your body to help you kind of fight those things so they don’t catch up to you when you’re 40, 50 years old.”