The workouts are underway at the 2015 NFL Scouting Combine.
Offensive linemen and tight ends participated Friday in timing and testing drills as part of the annual evaluation of more than 300 draft-eligible prospects by scouts and coaches from all 32 NFL teams.
Click here for Mock Madness 2.0 to see the pre-combine projections.
View photos from Friday's Scouting Combine workouts.
There are drills that use easy to understand metrics like how fast a player can run 40 yards in a straight line or how many times he can bench press 225 pounds, and there are also agility drills and (padless, no contact) blocking drills that serve as eyeball tests for talent evaluators who have studied game film.
Ail Marpet, out of Division III Hobart College, clocked the fastest time by a lineman in the 40 at 4.98 seconds, and Ereck Flowers out of Miami did 37 reps in the bench press.
What do those performances mean?
Tony Villiotti processed numbers to determine which measurable drill was most important to each position for nationalfootballpost.com. Villiotti looked at players who have started "one full season" and whether or not they were top performers among their position. He concluded that top performances by tackles are more important than any other position on the offensive line.
Villiotti also broke down which drills were most important for each position and determined the following were most important: 40-yard dash and broad jump for tackles; bench press and 20-yard shuttle for guards, 3-cone drill, bench press and broad jump for centers.
Of course there could be a situation where a player enters the combine as a tackle and slides into a guard spot, a la Zack Martin, who was an All-Pro guard as a rookie for Dallas after playing tackle at Notre Dame.
NFL Media analyst Mike Mayock has floated that scenario as a possibility for Brandon Scherff, and the Iowa left tackle who won the 2014 Outland Trophy said that would be fine with him during his media session Wednesday, saying, "whatever you need, I'll play wherever."
Scherff told reporters that he didn't think it would be a challenge to play guard.
"I like run blocking, and you'd be a little closer and also get help from the center," Scherff said. "It would be a smooth move for me, but like I said, I'll be happy to play wherever they want me to play."
Ali Marpet, OT, Hobart College, 4.98 seconds
Jake Fisher, OT, Oregon, 5.01
Laurence Gibson, OT, Virginia Tech, 5.04
Brandon Scherff, OT, Iowa, 5.05
Terry Poole, OT, San Diego State, 5.09
Bench press (225 pounds)
Ereck Flowers, OT, Miami, 37 reps
Mitch Morse, OT, Missoui, 36 reps
Sean Hickey, OT, Syracuse, 35 reps
Mark Glowinski, G, West Virginia, 31
Cameron Erviing, OT, Florida State, 30
(tied) Ali Marpet, OT, Hobart, 30
Laurence Gibson, OT, Virginia Tech, 33.5 inches
T.J. Clemmings, OT, Pittsburgh, 32.5
(tied) Rob Crisp, OT, N.C. State, 32.5
(tied) Jake Fisher, OT, Oregon, 32.5
Andrew Donnal, OT, Iowa, 32.0
(tied) Donovan Smith, OT, Penn State, 32.0
Laurence Gibson, OT, Virginia Tech, 9 feet, 5 inches
(tied) Mark Glowinski, G, West Virginia, 9-5
(tied) Terry Poole, OT, San Diego State, 9-5
Cameron Erving, OT, Florida State, 9-4
(tied) Mitch Morse, OT, Missouri, 9-4
Jake Fisher, OT, Oregon, 7.25 seconds
Ali Marpet, OT, Hobart, 7.33
Cameron Erving, OT, Florida State, 7.48
Jarvis Harrison, G, Texas A&M, 7.51
Ty Sambrailo, OT, Colorado State, 7.54
Jake Fisher, OT, Oregon, 4.33 seconds
Ali Marpet, OT, Hobart, 4.47
Mitch Morse, OT, Missouri, 4.50
T.J. Clemmings, OT, Pittsburgh, 4.54
Laurence Gibson, OT, Virginia Tech, 4.56