We have spent the summer months at Scouts Inc. studying the game tape of all the top draft-eligible college football players entering the 2014 season, with an eye toward their potential selections in the 2015 NFL draft. Keep in mind, these are just preliminary evaluations, as how each player performs this season, plus their performances in the entire pre-draft process, has the potential to significantly alter their draft stocks leading into the 2015 draft.

But even though much can change, the preseason scouting process serves as a valuable foundation for the more than 130 players we evaluated on tape. Be sure to check back next week for the launch of our DraftTracker, including rankings and scouting reports on every 2015 prospect.

For now, here is a look at our top 2015 NFL draft prospects at each position, including an abbreviated version of each player's scouting report, entering the 2014 college football season.

Offense

Quarterbacks

1. Marcus Mariota, Oregon Ducks (Grade: 95)

6-4, 224 pounds

Mariota surprised many by returning for his redshirt junior season, and he enters 2014 as our No. 1-ranked prospect. He is a dynamic athlete who puts stress on a defense with his mobility both as a runner and a thrower. He has above-average elusiveness and rare straight-line speed, reminding of Colin Kaepernick with his long stride. Mariota has a quick, compact, over-the-shoulder release with well-above-average arm strength, so he can make all the NFL throws. While he needs to become more consistently accurate, he has made big improvements in that department since showing up on campus in Eugene. Continued progress with his footwork and balance will be important for scouts to see in 2014. And yes, Mariota benefits from the Ducks' up-tempo spread offense, which simplifies reads and creates bigger throwing windows, but he still rates very highly in terms of his decision-making and overall mental makeup. Bonus: His intangibles are outstanding.

2. Jameis Winston, Florida State Seminoles (Grade: 94)

6-4, 235 pounds

Last year's Heisman Trophy winner will be eligible for the 2015 draft, if he chooses to leave school early. He has a prototypical frame for the position and excellent arm strength, with the ability to drive the ball downfield and deliver the deep outs with very good velocity. His accuracy is inconsistent, as he misses within the strike zone too much on short-to-intermediate passes and sails some deep balls, but he has the potential to get better with improved mechanics. His decision-making is a bit inconsistent as well, but he shows good anticipation and the ability to beat blitzes and handle pressure. He has good pocket mobility and can make defenders miss and break a few tackles, although he doesn't project as a big-time NFL running threat. He has the confidence and presence NFL teams look for in QBs, but they will have to check into his past legal issues and off-field decision-making.

3. Brett Hundley, UCLA Bruins (Grade: 86)

6-3, 227 pounds