Sage Rosenfels is a former 12-year NFL quarterback who writes, does radio, and podcasts about the NFL and college football.

We are roughly three weeks away from the NFL Combine in Indianapolis. Over the course of a week, college football players from all over the country will be tested physically and mentally by NFL general managers, coaches, trainers, and doctors. The combine has become a "must-see" event for those who love the NFL. Fans are just as curious as the NFL teams to see how the players stack up next to each other. Most viewers don't realize there is much more to the combine, and it actually starts the day after each college player’s season ends.

The NFL, and those who run the combine, do their best to scour the country to find who they feel are the 350 college football players most likely to make an NFL roster. This is most definitely an inexact science. While every NFL team employs a handful of scouts to cover every nook and cranny of the college football landscape, there is no way to know exactly who is going to make it to the NFL.

When most NFL fans think of college football, their minds immediately jump to schools in the Power 5 conferences. While the majority of NFL players do indeed come from these larger institutions, some great players found their way to the NFL through smaller programs such as Northern Iowa (Kurt Warner and David Johnson), Texas A&M Kingsville (John Randle), or Chadron State (Danny Woodhead).

There is no way for the league to invite everybody to the combine as there just isn’t enough time to analyze every collegiate player. As a result, every college has their own pro day for NFL scouts and coaches. Have no doubt, there will be a superstar or two from the 2017 class that won’t be in Indianapolis the first week of March. Whether they have been invited or not, college quarterbacks have been preparing for the combine or their pro day for the last few months. The following is what many of them are going through.

First off, the NFL Combine isn’t football. Therefore, the players aren’t necessarily preparing to play football. For some, preparation started when their season ended around Thanksgiving. For others, their final game wasn’t until the college season wrapped up Jan. 9. Either way, the day the season ends is the beginning of their hopeful NFL careers.

Physically, these prospects are being trained for a quasi-track meet. Each player has different drills that they will be tested on and none of them require wearing a helmet or shoulder pads. Therefore the players, with the help of strength and conditioning coaches, have been working out to maximize their performances in these drills. Yes, they are lifting and running, which is what they’ve been accustomed to doing as college athletes. What has changed for these players are the particular workouts and drills in preparation for Indy.

For positions such as quarterbacks and offensive line, the 40 time isn’t something you stress about during college. Yes, it’s nice to have a good time as you compete with your teammates in college, but it’s not going to cost you millions if you run a slow time. Since these drills are the initial pieces of their NFL resume, the numbers they compile are stressed with the utmost importance. So, the training these players take part in are a reflection of these drills.

The lifting and running exercises are structured to maximize their combine numbers which may or may not be helpful for blocking and tackling. Players will spend hours and hours perfecting the first 10 yards of the 40-yard dash. They will be lifting weights to help maximize their vertical leaps. Strength coaches will even videotape and analyze the athletes as they practice the 3-cone, short shuttle, and broad jump. Every aspect of a player's technique is coached for maximum performance. Why? Because in the NFL, scouts and general managers must have reasons as to why they did or didn’t draft a player. It can also confirm what the coaches and scouts have already concluded in their film study.

All of the players should be getting trained “mentally” as well. Though many of the physical drills are now televised, what the fans don’t see is the never-ending interviews taking place behind the scenes. Since almost every coach, scout, and GM are in attendance, this is a perfect opportunity for them to interview the players they have been watching on film for the last two months. Though a player’s performance during their college career is vital, the teams want to know the mental state and capacity of the players they draft. Therefore, not only are there interviews with “football” people, there are also written, verbal, and psychological tests administered by psychologists to help each team get a thorough picture of the athlete’s mental state.

For quarterbacks, these interviews aren’t just a get-to-know-you session. Most of the time, the teams will ask the players to stand at a chalkboard and break down some of their favorite concepts from college. The players draw up the plays versus defenses they saw in college and teach the concepts to the coaches who are observing. Since there is such a wide variety of offenses and coaching in college football, I have heard these sessions range from impressive to mind-boggling. You’d be surprised by the lack of deep understanding of the complexity of the position by many college quarterbacks: in particular, to the way that complexity translates to the NFL game.

Just like the physical testing, the mental testing is also coached before the combine. Many agents will actually hire former NFL players, like myself, to teach prospective quarterbacks NFL offenses. Since most NFL teams use one of three different languages, having a basic understanding of each language helps with these interviews. The more an NFL team sees that the quarterback they are scouting already has a basic understanding of their offense, the more likely they could draft him. This is more important than ever, since currently so few teams keep three quarterbacks on their roster. They may need the quarterback they draft to be the backup right out of the gate. The complexity of the NFL game makes it almost impossible to teach a young quarterback an entirely new offense in just a few months. Having some knowledge of a team’s offense and language can be very valuable for a quarterback’s draft stock.

Once the preparation is complete, and the Combine begins, the players arrive to Indy in groups. First, the players are poked and prodded by team physicians and trainers. X-rays and MRIs are taken of injuries sustained while in college. Then the players are measured like livestock (height, weight, hand measurements, etc) which is followed by the bench press test (for the majority of players).

On the last day, the prospects finally make their way to the playing field. Here, they are put through a mix of timed activities such as the 40. They also take part in specific drills such as throwing, catching, and movements related to each position. Let us not forget that during this entire four-day event, each athlete is being interviewed nonstop by the franchises who have an interest in them. It’s a grueling four days, but extremely valuable for the teams and the players.

Once the combine is over, the prospects will also have private workouts with their college teammates at their university. The combine is the first chance for these athletes to make a good impression on NFL teams. The private workouts are a way for players to confirm or improve their combine scores. This entire process leads up to what most college football players have been dreaming about for years; to be selected in the NFL Draft. For the players lucky enough to be invited to Indy, the combine is a major step in their journey to fulfill those dreams.