The NFL Combine, which starts tomorrow and wraps up on Monday, is like nothing else in sports. It is a cattle market for players who are departing the college game to try and make an impact as a professional. There is millions of dollars at stake for the players who will be timed, measured and weighed while hordes of journalists and scouts look on. They will be poked and prodded by team doctors and then grilled by personnel executives in interviews where no topic is off limits. In short, it is the toughest job interview in sport. For some players their performance in Indianapolis will generate interest that their performance on the field did not. A quicker than expected time on the 40 yard dash or one of the many varieties of shuttle runs can pique the scouts interest and create some buzz with the myriad of independent bloggers who can sway popular opinion. Equally, a poor showing can damage a prospect’s chances, regardless of how well he performed for his university over his career. For most players however, the important stuff comes in the back rooms away from the glare of the cameras. Teams want to be as sure as possible that the players they draft do not have a hidden injury or medical condition, so their own doctors sift through medical records and test players bodies. For one or two this can be life saving. In 2011, TCU Offensive Tackle Marcus Cannon’s physical showed some irregularities and from it he was diagnosed with Non-Hodgkins Lymphoma. For Tight End Rob Gronkowski his combine was spent trying to convince teams he was fully healed from a back surgery that kept him out of the entire 2009 season and that it would not be a problem going forward. He ended up being seen as a risk by many teams despite being extremely talented. The New England Patriots drafted him in the 2nd round in 2010, absorbing the medical risk and ending up with a superstar player who was key in them winning Super Bowl XLIX. Gronkowski has suffered many injuries since joining the Patriots but he has largely been unhindered by back problems. Then there are the interviews. These can be as straight-forward as showing a player an on-field scenario and asking what he would do, to awkward questions about their family, friends and any past run-ins with the law. Dallas Cowboys Wide Receiver Dez Bryant was asked during one pre-draft interview if his mother was a prostitute. There are not many prospective employers that would think such a question could have any relevancy. A lot of college players entering the draft have some misdemeanor or other on their record, after all they are young men away from home and are often celebrities with their fellow students on campus. It is easy to see how they could falter, who among us didn’t make a silly mistake when we were young? But those incidents will be raked over and picked apart by teams desperate to ensure they select the right player come draft day. Robert Nkemdiche, a highly talented defensive tackle prospect this year, will have to answer questions about an incident in mid December when he fell through a hotel window in Atlanta, as well as reported marijuana use. If scouts are not impressed with his answers it will not matter how big and strong he is, some teams will simply refuse to touch him on draft day because they would see his risk of suspension for substance abuse and the worry he might not be able to control himself as too high. Draft picks are the best way teams have of replenishing their roster with young, fresh players and as a result teams covet them. Deciding to use a pick on a player is a huge gamble, not just in financial terms (Last years first pick Jameis Winston was given a $25 million contract) but it can have long-lasting ramifications on the entire team if it breaks badly. In 2007, with the very first pick of the draft the Oakland Raiders selected LSU Quarterback JaMarcus Russell. It was a pick that quickly blew up in their face as Russell bombed and was released 3 years later. He has not played a down since then and it took the Raiders years to recover. Poor draft selections can cost executives and coaches their jobs while good drafts can set teams up to be competitive for a long time. San Francisco and Seattle’s recent success is entirely down to great scouting and drafting, especially with late round selections. Seattle’s Richard Sherman, one of the best cornerbacks in the NFL, was taken 154th in the 2011 draft. Selections like that are gold dust to NFL organisations. All scouting is an inexact science but more than any other sport, NFL teams try to reduce the variables and quantify the unknowns. Teams will already have a list of productive college players that they will not touch on draft day for one reason or another and a list of guys they think could do something for them that they did not do in college. But for all their testing and research players will still fall through the cracks. Chris Harris Jr was undrafted in 2011, now he is a key part of the Super Bowl champion Denver Broncos defense. Aaron Hernandez was a 4th round pick in 2010 and a highly productive player. He is now in jail for first-degree murder, something no one could have predicted no matter what questions were asked of Hernandez before the draft. This weekend will be the most important one in many of the players lives and careers. It will be crucial for up-and-coming scouts and grizzled veterans alike as they try to gain ground in the industry. For fans it is a chance to dream of the amazing player your team might draft who will lead them to glory in the future. When the draft rolls around at the end of April the foundations for someone going earlier than expected on Thursday evening or falling back to late Sunday afternoon will have been laid down here.