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.Shaq Thompson, Washington 6-1, 228
The only question mark is whether or not he can hold up. He’s almost too good to be true in terms of all the things he can bring, but he’s not all that big and he’s not all that strong, but that doesn’t really matter considering his athleticism. He’ll get erased by the tougher blockers and linemen, and there’s no natural fit, but as long as he’s as quick as everyone expects, he’ll be fine. 

2.Bud Dupree, Kentucky 6-4, 264
Is he an NFL pass rusher? He has the tools and he has the upside, but he needs coaching. The interview process will be vital – the GMs and coaches are going to grill him. On athleticism and speed, he’ll be high on everyone’s board, but he needs to sell his upside a bit. 

3.Hau’oli Kikaha, Washington 6-3, 246
Can he hold up against power running games? He has decent size, but he gets beaten on a bit too easily and he takes lots and lots of big shots. The physical will be his biggest challenge after having knee problems over the course of his career. 

4.Kwon Alexander, LSU 6-2, 227
Can he diagnose? The interviews will be where he has to shine after mostly getting by on his great speed. Everyone is going to like him, but he has problems with his positioning – he makes up for mistakes by flying to the ball. In the drills, he has to be really, really quick and off-the-charts athletic to make up for his lack of raw bulk. 

5.Lorenzo Mauldin, Louisville 6-4, 252
Is he inside or out? Everything is there except for a set position – and fluidity. He’s not really an inside linebacker, and he’s not really an NFL pass rusher. He has to come out of Indy with the scouts being certain he’s an outside defender who could grow into a disruptive force. 

6. Max Valles, Virginia 6-5, 240
Is he ready to shine right away? Still a project, he has the basic tools and the potential is through the roof, but he needs time. He needs coaching and he needs a lot of polish, but he could still jack up his stock with a great workout – he has everything in place to just that. 

7.Geneo Grissom, Oklahoma 6-3, 264
Is he a small defensive end or a big linebacker? His workout might determine that. Not a finished product, he needs to look athletic and has to be smooth. Can he turn? Can he effortlessly cut in coverage? He’s one of the more interesting prospects considering his upside, but there’s still a lot of scouting to be done. 

8.J.R. Tavai, USC 6-2, 250
Can he run well enough? He’s a strange prospect because he doesn’t play like a natural outside linebacker. He’s not a top-shelf athlete and he was always banged up in one way or another. The scouts are going to love his potential and his fire, but he has to move well. 

9.Jake Ryan, Michigan 6-3, 236
Is he tough enough to handle the inside and/or quick enough to be a pass rusher on the outside? He should test and time fine, and there’s no questioning his fight or his leadership, but he might need help around him. He’s not quite as quick as was before suffering a torn ACL two years ago. 

10.Kyle Emanuel, North Dakota State 6-3, 246
A dangerous pass rusher and playmaker behind the line at the lower level, he has to bring the speed and cutting ability to eventually become an NFL edge rusher. He might not be powerful against the stronger run blockers, but that’s not going to be his game – he has to look the part. 

11.Martrell Spaight, Arkansas 6-2, 231
Does he have the raw NFL tools? He turned into a good SEC football player after starring at the JUCO level, but can he move well enough? Does he have the bulk? He can hit, but he might not look the part and might not time well – he has to come close. 

12. Alani Fua, BYU 6-5, 234
If he’s going to be a pure pass rusher, he has to show off the speed and the burst. Is he going to be physical enough for his frame? He has the size to add more good weight and be more of an end, but first he has to rock the numbers. He just might be one of the talks of the combine if he works out like he’s supposed to. 

13. Deion Barnes, Penn State 6-4, 260 (Not Invited)
At some point he’ll have to look like an outside linebacker. He’s not quite strong and bulky enough to work as a true NFL end, and he’s not athletic enough to be a high-end 3-4 pass rusher, but there’s enough talent there to find a role in someone’s defense. 

14. Mark Nzeocha, Wyoming 6-3, 239
How bad is his knee? It might not be the worst thing in the world to get a redshirt year to take to NFL coaching – he’s still very raw and needs lots and lots of work – and he might get it. A phenomenal physical prospect, he’ll be a flier, but a good one. First his knee needs to heal. 

15.Obum Gwacham, Oregon State 6-5, 236
A way-undersized defensive end who’ll be a better fit at outside linebacker, can he handle another position change? The former wide receiver can move, but he’s still trying to figure out how to play defense and needs time no matter where he plays. He has to look like a defensive player, even if Indy is purely a workout. 

16. Xzavier Dickson, Alabama 6-3, 268
Is he too bulky to be an outside linebacker? Is he quick enough? Is he strong enough to think about being an end? He doesn’t really have a true position, and he’s not going to do anything in pass coverage. He has to sell the scouts that he’s more than just a part of a puzzle. 

17.Tony Washington, Oregon 6-3, 250
Does he have any special traits? Can he move at an NFL level and does he have anything that stands out? He’s a good, sound, versatile defender who should find a spot somewhere in an NFL mix, but he has to look like a pass rusher. He has to fly though the short drills. 

18.Edmond Robinson, Newberry 6-4, 230
The bench matters. There are the obvious concerns and questions about his potential after coming from the lower level, but the scouts want to see if he has the strength and the pop. He’s a tall, rangy defender who can move, but he could also use about ten pounds of good weight. 

19. Yannik Cudjoe-Virgil, Maryland 6-2, 250
He’ll be great in interviews and he has the right attitude, but he doesn’t really have an NFL position and isn’t quite athletic enough. Can he zip around the short drills? He has to be quicker than fast – he has to be fluid. 

20. Neiron Ball, Florida 6-3, 230
The physical will be mostly what matters. From brain surgery early in his career, and other injuries he’s had to deal with, he has to be checked out closely. A special teamer, he’ll have to pass the pokes and prodding part of the program to have any hope of being drafted.