Too many fans believe that the NFL Scouting Combine should have a very limited impact on draft grades since the event is often scoffed at as "the underwear Olympics."
Game tape can show an evaluator how a prospect plays and it reveals their strengths, weaknesses and tendencies. However, it's not always easy to get a feel for a player's speed or athleticism from watching the tape. One player might look fast because he's playing against a lower level of competition, and then come out and run slow at the combine.
A cornerback from a name-brand school in a competitive conference might not blow your doors off with his athleticism or speed on tape, but then he might prove at the combine that he's more than capable of changing direction quickly or running with long speed.
Understanding which drills are most telling for each position group is the key for reading the tea leaves that are combine results. With that said, here are some of the most notable players whose draft grades jumped or dropped after their combine showing in Indianapolis. Click here to see all of my grades for prospects in this year's draft.
Risers
Carson Wentz, QB, North Dakota State (from 6.23 to 6.51): My grade essentially changed from "chance to be a good starter" to the lower end of "good starter with Pro Bowl potential". Wentz looked rock-solid in his workouts and had a commanding presence throughout the process. The discussions I had with team executives who raved about his maturity, intelligence and poise in their interviews really sold me on bumping his grade. The physical traits and tools were always there, but adding the "intangibles" piece of the puzzle helped finalize my grade.
Eli Apple, CB, Ohio State (from 5.68 to 6.00): Apple's tape was solid, but there was nothing to really get excited about. He has his standard strengths and weaknesses, but I was really interested to see how he would measure and run. It turns out that he was as big as advertised, measuring in at almost 6-foot-1 and 200 pounds. Apple's 40-yard dash time of 4.40 seconds, including a blazing 10-yard split (1.47 seconds), immediately checked a huge "size/speed" box that is often necessary for a better draft grade.
William Jackson III, CB, Houston (from 5.65 to 5.93): While he has a slight hitch in his transition from press coverage, Jackson's tape showed plenty of recovery speed and fantastic ball skills. Jackson measured at more than 6-feet tall with slightly above average arm length and a smoking fast 40 time of 4.37 seconds. An NFL defensive backs coach said he had seen my initial grade on Jackson and questioned how I could see Jackson's size, speed and ball skills and still give him what amounted to a third-round grade. I answered that I was worried about his tackling. He reminded me that cornerbacks get drafted based on ball skills and not tackling. Thanks, coach.
Sliders
Su'a Cravens, OLB, USC (from 6.10 to 5.89): Cravens' lackluster combine results combined with concerns about his position fit played into this drop. I love the guy on tape, but he has to play near the line of scrimmage to have the impact that I'm projecting and at just under 6-1 and 226 pounds, I don't know how feasible that is. UCLA center Jake Brendel topped Cravens' vertical leap by an inch (28 to 27). Cravens didn't run, but his lack of size, explosiveness and questions surrounding a scheme fit forced me to drop his grade despite my love of the tape.
Scooby Wright, LB, Arizona (from 6.02 to 5.75): My grade went from "chance to become a good NFL starter" to "chance to become early starter". I still really like him as a prospect and his production speaks volumes, but he's coming off of a leg injury and he ran a 4.90 40 -- those things hurt him. Wright's explosion efforts and quickness drills weren't good enough to keep me from dropping his grade.
Harlan Miller, CB, Southeastern Louisiana (from 5.78 to 5.59): I love Miller's tape and his willingness to stick his nose into run support, but I can't ignore his workout. For one, Miller measured in at 182 pounds, which is awfully light for a physical cornerback who will be taking on much bigger running backs. Miller managed just six bench-press reps and ran a 4.65 40. He's thin, lacks strength and didn't run well. He tested poorly in quickness drills as well. Love the tape, scared by the workout.
Follow Lance Zierlein on Twitter @LanceZierlein.