The former first-round pick in 2010 hasn't played since Week 6 of the 2011 season after suffering a concussion in a loss to the 49ers.
“It's disappointing, but I'm a glass half-full kind of guy,” Best told Detroitlions.com in late November.
“To me it's just a minor setback and I'm still working and still staying ready because when I do get my chance I'm going to be ready.
“(The doctors) said I couldn't play this season, but they didn't close the door (on the future). It doesn't matter how long it takes me, as long as my body is fresh, then I'm going to stay ready to play.
"If they give me a chance, and they say it's safe for me to play, then I'll be out there. I'm doing everything I can to get back."
Through the first 21 games of his professional career, Best was just as much of an asset in the passing game as he was as a runner. He had six rushing touchdowns and 22 runs of 10-plus yards.
Best amassed 85 receptions for 774 yards and three more touchdowns, which is an average of more than four catches per game.
Since losing Best, the Detroit Lions have a 9-19 record (including the playoffs), but his impact - or lack there of - isn't just relegated to the win-loss column. Look at his impact on other players around him, particularly receiver
In those 21 games Johnson played with Best over the 2010 and 2011 seasons, Johnson recorded 21 touchdowns. In the subsequent 27 games Best has missed, Johnson has 12 total touchdowns.
Best is a potent red zone weapon with his unique ability to score both as a runner and receivers. It's one of the big reasons Detroit Lions general manager Martin Mayhew is on the lookout for a replacement this offseason if it's determined Best can't play.
That type of player out of the backfield can't be guarded by a linebacker in most cases and doesn't allow a defense to focus solely on Johnson, which we've seen more and more of since Best has been absent.
In a Week 1 victory over the Rams this season, four Rams defenders covered Johnson in the end zone on a 2nd-and-goal play with 15 second left in the game, allowing running back
It makes a difference how defenses defend when there's the threat of the big play in the backfield, especially if it's from a dual-threat back like Best, Reggie Bush (Dolphins) or the Saints' Darren Sproles.
Former Detroit Lions receiver Herman Moore had 62 career touchdown catches. Of those, 52 came in the 105 games played with Hall of Fame running back Barry Sanders, which is a touchdown rate of 52 percent.
In the 28 career games Moore played without Sanders, he had seven touchdowns (a rate of 25 percent).
Johnson had one of the greatest seasons in the history of the game for a receiver with 122 catches for 1,964 yards this season, but had only five touchdowns and only two in the red zone.
Granted, he was tackled six times inside the 2-yard line, but teams made a concerted effort to keep the ball out of his hands in the red zone. That was made easier by the fact that the Lions lacked an explosive weapon like Best out of the backfield.
It's why filling that role for next season is vital to the Detroit Lions' offense.