Concussions are unlike any other sports injury. Symptoms and issues vary from person to person.

To date, Sidney Crosby of the Pittsburgh Penguins is probably the most famous athlete who has missed considerable playing time due to a concussion and then returned. He was out for most of a 14-month stretch.

We can’t compare him exactly with the Lions running back Jahvid Best, who has been ruled out at least for now  — 364 days following his concussion.

But Crosby is proof that a player can return after an extended layoff due to concussion symptoms.

Crosby was first concussed on Jan. 1, 2011, in the Winter Classic. However, he was back in action on Jan. 5 and got hit again.

He did not play again that season.

After being cleared for contact nine months after sustaining the concussion, Crosby played in his first game a month later on Nov. 21, 2011. Then he played in eight games before taking an elbow to the head.

  He was out another three months before returning for good on March 15, 2012, more than 14 months after his first concussion. He must have done well because on June 28, 2012, he signed a 12-year, $140.4 contract extension.

 Again, we can’t compare Crosby to Best day for day, game for game, symptom for symptom.

  But perhaps there is hope for Best even though he’s been out for a year. It’s got to be a long shot, though.

 (Follow @PaulaPasche on Twitter.)