For those invited and participating in the 2015 NFL Combine, what matters? What’s the most important thing to watch out for? They’re all talented and they all have elite skills, but there are keys that every scout and GM will be looking at. Here’s what each prospect has to prove … 

1.Trae Waynes, Michigan State 6-1, 182
With his size and toughness against the bigger receivers, and strength against the run, now he just has to be fast to be the first corner taken. Is he smooth? Is he fluid? Straight-line speed will be key, but to be someone’s must-have, shut-down corner, he has to look like he could get stuck on an island. 

2. P.J. Williams, Florida State 6-0, 196
Can he be the first corner taken? He has all the tools and all the abilities, but if he looks more athletic and faster than Trae Waynes, he might be seen as the main shut-down corner. Physical and quick, a 4.4 might be enough to be a top 20 pick. 

3.Ifo Ekpre-Olomu, Oregon 5-10, 195
Just how bad is his knee? He might need a redshirt year, but if he’s given time to heal up, and if he never suffered the knee injury, he’s be the No. 1 corner taken. One of his question marks was his raw speed, but he’s not going to be able to show that yet. Obviously, the physical is the most important part of his weekend. 

4.Jalen Collins, LSU 6-2, 198
Is he ready? Everything is in place as yet another LSU prototype, but he might need a little time after only really making a splash for a year. He has to hit up to his size, and he has to be fluid, but if he rips up the 40, look out – he could sneak into the late first round if he rocks the workout. 

5.Marcus Peters, Washington 6-0, 198
The interview process has to go perfectly. He’ll say all the right things, and he’ll look the part of a potential star on the field, but can he get by his attitude and issues after having problems with the new Washington coaching staff? He has first round talent, but he could freefall if no one wants to deal with his baggage. 

6.Quinten Rollins, Miami Univ. 6-1, 203
How long does he need before he becomes a real, live corner? The upside is limitless, but he’s a basketball player still figuring out how to be a next-level corner. As long as he runs well and moves as smoothly as any of the other corners, he’ll make himself an intriguing second round pick. 

7.D’Joun Smith, Florida Atlantic 5-11, 190
As long as he’s fast and as long as he’s quick and as long as he cranks out a great 40, he’ll be fine. Teams stayed away from him after he turned into a devastating playmaker, so he needs a lot of tape work for the scouts, but more than anything else, he can’t be slow. 

8.Senquez Golson, Ole Miss 5-9, 176
Is there any way he can look physical? Not big enough, he’ll be manhandled by the tougher NFL targets, and while he’s a fighter, that might not be enough. While he’s a true baller, he doesn’t have the body to hold up if he has to make a lot of big plays. The physical might turn out to be the key to his stock. 

9.Kevin Johnson, Wake Forest 6-1, 175
If it’s possible to show some strength of physical abilities, he might rocket up the charts. He’s athletic and he’s fluid, but he’s not all that strong and he’s too lanky. Anything he can do – ten reps on the bench? – to give the appearance of being tough will be a big help. 

10.Alex Carter, Stanford 6-0, 202
All eyes will be to see how he looks in the agility drills. No one questions his ability to get in against the run, and he’s a veteran who knows what he’s doing, but he might be more of a safety than a true corner. Can he work the field? Can he sit on an island? His workout could up his draft stock into the second round if he’s quick. 

11. Ronald Darby, Florida State 5-11, 195
He has to sell the scouts that he can hit. There might not be a faster corner in the draft, and he has the size and skills, but will he tackle anyone? If he cranks out a 4.3, no one will care if he’s not a middle linebacker against power running games. The interview will be vital considering he was named and involved – and cleared – in the Jameis Winston sexual assault issue. 

12.Lorenzo Doss, Tulane 5-11, 187
The 40 time, the 40 time, the 40 time. He’s an overaggressive ball-hawk – in a good way sometimes – and he’s not going to tackle anyone, but his stock is going to totally and completely depend on his 40. He’ll be fine if he comes in around a 4.5, but a 4.6 or worse sinks him. 

13. Steven Nelson, Oregon State 5-11, 194
How well does he move? He has good size, and he’ll beat up receivers, but can he cut? Can he plant and go at an NFL level? He’s going to have to hit and fight against the better targets, but the athleticism has to be there. 

14.Josh Shaw, USC 6-1, 200
He might be among the most interesting interviews in Indy. He’s more of a safety than a true corner, and he has to run well and be smooth to not be seen as a free safety, but he has to be solid when talking to GMs and coaches after all the drama. 

15.Craig Mager, Texas State 5-11, 195
Really, really tough, he’s going to be a scout favorite and the coaches are going to love him, so now he has to show he can move. He doesn’t have to be blazing, and he doesn’t have to dominate the workout, but as long as he’s just okay, someone will want him as a possible safety if he doesn’t turn into a corner. 

16.Quandre Diggs, Texas 5-10, 195
He’s a better pure football player than he ever received credit for, and now he has to have the tools. His lack of bulk is going to be a slight concern, and he’s not really built to be a powerful defender, but he needs to open some eyes with a good 40 and by looking physical. 17.Ladarius Gunter, Miami 6-2, 198
Be loose. He doesn’t have to be lightning quick considering his size, but he has to be straight-line fast and he has to look like he has the tools to work with. He can’t come off as stiff – the smoother, the better. He can’t afford a slow 40, either. 

18.Kevin White, TCU 5-10, 174
The measurements are going to matter. He’s tall, but he doesn’t really look like an NFL corner. He’s not built to be a big hitter, and he doesn’t have the overall length. He has to somehow look physical, and the raw hand/arm/length numbers are going to be scrutinized. 

19.Jacoby Glenn, UCF 6-0, 186
Speed, speed, speed. He’s a baller who always finds his way around the ball, and he’ll do whatever is needed. Scouts are going to be looking for reasons to make their case, but they can’t do it with a 4.6. He has to be in the low 4.5s, and if he comes up with something big, his stock blows up. 

20. Charles Gaines, Louisville 5-11, 180
Will a team be patient? Either he’s just scratching the surface and he has the upside to be an absolute steal, or he’s too raw and needs too much technique work after starting out his career as a receiver. He could be someone’s pet project in the second round with a fantastic workout. 

21.Doran Grant, Ohio State 5-11, 193
Is there anything special about his game or his tools? He has decent size, and he’s a willing fighter, but he was a good cog on a great defense. There has to be something about his workout that opens up eyes – he has to look smooth and he can’t afford any mediocrity in the 40. 

22.Bobby McCain, Memphis 5-11, 195
Just how smooth and explosive is he out of his cuts? The 40 time is vital – he can go from a late-round flier to a possible fifth-rounder with a great run. He’s a ball-hawking playmaker, so the scouts are going to want to find reasons to take him. He has to provide them. 

23.JaCorey Shepherd, Kansas 5-11, 199
Get tough. He’s a good playmaker who can hold his own, and he has the body to possibly get a little bit bigger and stronger, but he has to prove to everyone that he can hit. His future might be as a versatile option for several spots, and now he has to give the scouts a reason to be creative. 

24. Garry Peters, Clemson 6-0, 190
He has to show the feet. He was great as a physical corner who could shove receivers around, but he has to show off the quickness to make him workable for a coaching staff. He’s a good hitter with room to get a little bigger and stronger, and now it’s about his athleticism and speed. 

25. Deshazor Everett, Texas A&M 6-0, 193 (Not Invited) 
It’s going to be tough to stand out on his pro day compared to being in Indy, but he needs to be as quick as possible. He’s not going to blaze away, and he’ll eventually be a versatile safety and a special teamer if he sticks, but his options open up if he can move. 

26. Imoan Claiborne, Northwestern State 5-11, 187 (Not Invited)
The lower-level competition will be tough to overcome, but he can move and he’ll look the part. The 40 time and the straight-line speed will be the differentiator – he has to be around a low 4.5 to be draftable. He’ll be a special teamer who could be a great late round flier if he’s fast. 

27. Troy Hill, Oregon 5-11, 175
Can the scouts get past his body type? He doesn’t really look like a physical hitter in any way, but he’s an athlete who can move. If his money will be made on his speed and quickness, then he has to fly. The interview process – after having some issues getting suspended a few years ago – will be vital. 

28.Justin Coleman, Tennessee 5-10, 188
More of a football player than a raw prospect, he needs to come up with something that stands out. Is he fast enough? Is he explosive enough? Is he strong enough? He has to overcome his lack of bulk and look versatile enough to be used as a backup at several spots. 

29.Anthony Jefferson, UCLA 5-11, 192
Is he a corner or a safety? He might be a tweener, and not in a good way to be a starter at the next level. He might turn out to be a great backup for several spots, but does he have the speed to be a corner? Does he have the pop to be a safety? He has to give scouts a reason to get excited. 

30.Damian Swann, Georgia 5-11, 180
A better football player than a prospect, does he have the basic tools? He looks fine on tape, and he was a good, sound SEC corner, but does he have enough of a game to make any sort of an NFL impact? He might be just too slow and just too small to find a sure-spot in a secondary. 

31.Byron Jones, Connecticut 6-1, 196
He has the size and he has the leadership and personality, and now he needs the workout. He might not have the raw speed or athleticism to be a starter, and he’s trying to get over a shoulder injury, but he’s the type of prospect teams will want to draft. A good run might make that happen. 

32. Donald Celiscar, Western Michigan 5-11, 183
A tough, physical football player who isn’t afraid to get his nose dirty, he’ll be draftable with a few good runs and some explosiveness. He could be a free agent with a bad 40. The sprint might be a bit overrated, but not in this case. 

33. Julian Wilson, Oklahoma 6-2, 201
Is he a football player? He looks like the prototype, but he gave up way too many big plays. He’s absolutely everything you’d want in an NFL corner except for one problem – he’s not that great at playing football. He should blow up the drills, though. 

34. Tye Smith, Towson 6-0, 170
Along with the small-school issues, he has to get past his way-too-thin body type. He has to be really fast, really quick, and really explosive to overcome the basic issues. He has to show something to make him draftable.