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(Yahoo!) The Tampa Bay Buccaneers should have two top passers to choose from with their top-overall NFL draft pick, depending on if Jameis Winston and Marcus Mariota both decide to leave school early. To borrow a phrase from former defense secretary Donald Rumsfeld, they are dealing with some known unknowns.

In the case of Winston, one of these known unknowns is clear: he makes questionable decisions off the field. Some of these decisions are silly. Some are serious. The best quarterbacks, from Drew Brees to Tom Brady to Russell Wilson, rarely if ever make questionable decisions off the field. If the Bucs take Winston with their No. 1 choice, they are not drafting a player who has been a perfect citizen. But there's a layer of concern on the field as well.

Winston comes from a line of Jimbo Fisher products who were first-round failures. Fisher mentored JaMarcus Russell at LSU, then Christian Ponder and E.J. Manuel at Florida State. None were anywhere near as reliable as pros as they were under Fisher, although Manuel has had only two seasons in Buffalo to establish himself.

Winston looked different. From the first snaps he took as a redshirt freshman in 2013, on the road in a one-sided win over Pittsburgh, Winston looked incredibly comfortable under pressure. Many said he looked more like a pro passer in that first game than Manuel did in his last game in Tallahassee. Winston went on to win that night and 25 straight games as a starter after that. He has lost only one game since high school.

Yet there are credible arguments that he is a "system quarterback," with Fisher being the "system." His first-half lethargy throughout the 2014 season, followed by swashbuckling second-half comebacks, suggests it was Fisher who helped Winston figure out defenses at halftime. Even in his best games, like the Seminoles' national title victory over Auburn, Winston had a tendency to be overexcited in the first half, throwing erratically before finding his rhythm. One of the more memorable sights of the Florida State loss to Oregon last week came when Fisher yelled at Winston to "calm the [expletive] down" or be benched. Winston has had to calm down often over the course of his college career.

None of this is to say Winston doesn't warrant the Bucs' careful consideration. Very few freshmen quarterbacks go unbeaten and win national titles. Very few have the kind of arm made famous not only on the football field, but on the baseball diamond as well. And very few quarterbacks have the kind of charisma Winston possesses; his teammates seemed to love him in good times and bad. A lot of people compare Winston to another Heisman winner, Johnny Manziel. Yes, both have off-field decision-making issues. But to suggest that they are comparable as pro prospects is not fair to Winston as he is a legitimate first-round talent who stays in the pocket and sees the field very well.

It's hard to know how much of Winston's success is due to Fisher's coaching, just like it's hard to separate Marcus Mariota's extraordinary career from the long line of Oregon quarterbacks behind him. The Ducks haven't produced great NFL passers, dating back to Joey Harrington and before, and it's uncertain how much Mariota is benefiting from a very successful college system. With Mariota, just like with Winston, there is a strong "this time it's different" argument to be made. Mariota has won the Heisman, taken the Ducks to a national title game, and nobody would lump his ability in with Dennis Dixon or Jeremiah Masoli. He's a step above.

And yet Mariota is known for leaving the pocket, which hasn't worked all that well at the next level. NFL defenders will get to the edge just as fast as Mariota can, and they will be able to keep up with a fast-paced offense far better than the teams in the Pac-12 North. It's still unclear if the offense of former Oregon coach Chip Kelly can succeed over the long term in the NFL, although early results are promising. If Mariota can't run, and if he's forced to win a game purely from the pocket, can he do it? That's unknown.

Making matters even more uncomfortable for the Bucs is their head coach. Lovie Smith is hardly known as a developer of quarterbacks. He brought in Josh McCown from Chicago, and that failed. His offensive coordinator, former Pac-12 wizard Jeff Tedford, left for a head coaching job in the CFL after a sudden illness during the 2014 season. The team's offensive line is poor, and it is not likely to get better right away. Whomever is taking snaps for Smith next season – even if it's Mike Glennon – will have to learn a new system and take quite a few sacks along the way. That doesn't bode well for Winston, and it sure doesn't bode well for Mariota.

Smith is, in a way, the most troubling "known." We know he is not an offensive mastermind. Hiring someone like Marc Trestman to work with McCown and then train Winston or Mariota might be a good option, but it doesn't settle the nerves of those who haven't seen any history of offensive firepower under the Bucs' head coach.

The history of No. 1 overall quarterbacks is littered with whiffs. For every Andrew Luck, there's a Tim Couch. Jameis Winston could be Ben Roethlisberger, just like Marcus Mariota could be Aaron Rodgers. But getting drafted to a team with a substandard offensive line and a defensive-minded coach isn't a good harbinger when the quarterback in question causes so much debate among pundits and fans alike. There are style questions for both Winston and Mariota, and there are system questions. Both must be answered over the coming weeks leading up to the draft.

There is one thing that should give the Bucs excitement, though, and that is the idea of a No. 1 pick throwing to Mike Evans for years to come. Considering the Bucs had two wins in 2014, Evans is about the best "known" there is.

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