When an NFL team with a high draft pick is not completely sold on a quarterback, they tend to let that player slide, which can sometimes turn into a free fall.

Just ask Aaron Rodgers, Geno Smith or Johnny Manziel. But it is not exactly clear why Marcus Mariota has fallen to from first to sixth overall in ESPN NFL Draft expert Todd McShay's second mock draft.

McShay projected in mid-Dec. that Mariota would go first overall to the Tampa Bay Buccaneers and Jameis Winston would go second to the Tennessee Titans. The pair of quarterbacks are starkly different, in playing style and personality, so it is a bit of a jarring turnaround from one to the other.

In his analysis of Mariota, who would theoretically be drafted by the New York Jets, McShay said the Oregon QB "could slide even further than this on draft day." In a draft thin on quarterbacks and teams that need a passer, McShay would probably be right, if Mariota drops.

BucsNation.com recently reported that ESPN's NFL insider Chris Mortensen has been indicating that Tampa Bay is lining things up to pick Mariota. First, there is offensive coordinator Dirk Koetter and his old friend Mark Helfrich, Mariota's coach at Oregon. Then there is quarterbacks coach Mike Bajakian, who has a certain familiarity with a spread offense. Lastly, there is former Bucs coach Tony Dungy, who is reportedly sold on Mariota.

But BucsNation.com also acknowledged that Tampa Bay's head coach, Lovie Smith, may be eyeing Winston more favorably. Winston is believed to be leaps and bounds more refined as a pocket passer, but his off-field antics - major and minor - are worrisome.

Unfortunately at Tampa Bay's mercy are the Titans. If they want either QB, they have to wait and see which one the Bucs take. So McShay's second mock draft seems to suggest that the Titans are not going to worry about any QB and just take Leonard Williams, the imposing defensive lineman from USC.

CBS Sports and SB Nation are still among the publications that believe Mariota will not fall beyond the top two picks, but it really could be a free fall for either of the two QBs. Then the question becomes, if Mariota falls past Tampa and Tennessee, do the Philadelphia Eagles try to move up then?

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