How top prospects fared on NFL combine Day 1

Does Fournette's 40-time end worries about his weight? (1:34)

The NFL Insiders crew examines what Leonard Fournette's 4.51 unofficial 40-yard dash means for his draft status. (1:34)

INDIANAPOLIS -- The NFL combine is just a small sliver of the evaluation process. Evaluators often use it to confirm their scouting report from the tape. Let's take a look at how a few of the big-name prospects performed on Friday, when running backs and offensive linemen went through workouts.

Players analyzed below include: Stanford's Christian McCaffrey, LSU's Leonard Fournette, Florida State's Dalvin Cook, Tennessee's Alvin Kamara and Clemson's Mike Williams.

Christian McCaffrey, RB, Stanford

Rank entering combine: No. 37 overall | No. 4 RB

Coming into the day, I thought McCaffrey would run the slowest 40 time of the top four running backs (Fournette, Cook, Kamara). He's really shifty and accelerates quickly, but I wasn't sure what his top-end speed would be. McCaffrey ended up with an official time of 4.48, which is outstanding and the fastest time of this group. Where McCaffrey really shined, though, was with a 6.57-second three-cone. That's the second-fastest time among RBs since 2006, and it jibes with his short-area quickness and route-running ability on tape. And the Stanford product put on an absolute show during pass-catching drills. He just looks so natural catching the ball. If you draft McCaffrey, you're getting a really good running back and wide receiver. You can't say that about many guys. There's a good chance he goes in Round 1 after his performance.

Leonard Fournette, RB, LSU

Rank entering combine: No. 3 overall | No. 1 RB