Johnson rushed for 663 yards and four touchdowns as a freshman in 2004. Ever since then, he has been one of the most productive backs in college football. As a sophomore, he earned All America honors after rushing for 1,755 yards and 25 touchdowns. Johnson continued that success a year later, rushing for 1,087 yards and 16 touchdowns to go along with 312 yards and a touchdown on 25 receptions, despite missing two games due to injury. As a senior Johnson shared carries with Jeremy Avery, so the numbers dropped. He still ran for 766 yards and 13 touchdowns in addition to the 229 yards on 22 catches as a receiver.
Strengths
Johnson is a tough runner that battles for extra yardage. He is very good between the tackles. He attacks the line of scrimmage, while showing the ability to make the first defender miss and get into the open field. Johnson has decent speed and has shown the ability to break off the long run and not be caught from behind. He has also developed his receiving skills over his career, and is now a reliable option as a receiver out of the backfield.
Weaknesses
Johnson lacks ideal size for a feature runner. He has a lean frame, and does not pack enough punch to run between the tackles consistent at the NFL level. Durability is also an issue, as he has been limited and missed time at various points in his career due to rib, knee, lung and kidney injuries. Already having durability questions because of your size, it is not good to actually have the injury history to go along with it.
Future
Johnson has been a very productive college back, but his pro potential is very limited. He projects well as a backup running back because he is tough, intelligent, and can catch the football. Johnson tested out well at the combine, and may have actually helped his draft stock. He had the fastest official RB time at the combine, running a 4.46 at 212lbs. This could have pushed him up into the middle portion of the draft, considering the on field success he had during his college career.