The F in F-back has meant failure the past few seasons. 

The F-back refers to a player, usually a tight end, who lines up at various places along the line of scrimmage.  Sometimes the F-back is on the line as a true tight end.  Other times, he lines up outside the tight end as a wingback. Most of the time, the F-back flexes into the backfield and acts as a fullback, leading the tailback up the middle on run plays. 

It's the failure to execute this final responsibility which doomed Anthony Fasano in Dallas.  He was solid playing on the line, but his inability to engage and move inside linebackers, coupled with Deon Anderson's '07 injury problems, meant the Cowboys had to use Jason Witten as their f-back and put Fasano on the line.

This ran counter to the team's wishes.  Witten was the better down-the-field option, so putting him in the backfield diminished his receiving talents. 

Last year, Tony Curtis got his shot at as F-back, while rookie Martellus Bennett started as a pure tight end.  Curtis' inability to function as a lead blocker saw Bennett getting more and more reps as F-back as the season progressed.  After the bye, Dallas relied a lot on diamond formation popularized by Mike Sherman's Packers, where Witten and Bennett would line up as offset-I fullbacks, one to each side of the line.  At the snap, they could either dash upfield on patterns or both lead the running back inside.

Dallas did not offer Curtis a tender last week, meaning the team will again look for a blocking tight end or, perhaps, a true fullback.

Spread offense have proliferated in college football and have greatly diminished the number of fullbacks sent to the pros.  This is the main reason why Dallas has stocked up on tight ends in recent years.  This year sees a handful of legitimate fullback prospects available.  They're led in some order by LSU's Quinn Johnson and Syracuse's Tony Fiammetta.

Johnson is a true blunt instrument, a vicious lead blocker.  That skill alone may prompt the Cowboys to call his name draft weekend.  He is rather one dimensional, from all published reports.  His 40 times fall in the 4.85 range and he lacks great hands. 

Fiammetta has the more complete game and may also draw serious Cowboys attention.  He blocks well, though not as well as Johnson.  He is faster, shiftier and a far better receiver.  Given that any fullback would have to play special teams, I'd prefer Fiammetta, who times in the 4.6 range.

Stories on fullbacks often draw groans from the blogging faithful.  Fullback lacks sex appeal.  That said, I find the circumstantial evidence for a fullback pick quite strong.  Dallas will surely improve its run percentage this year.  Curtis is gone, meaning Deon Anderson is the lone lead blocker on roster.  Anderson's game plateaued last year.  He's an okay blocker, but you would never compare his blocking skills to Moose Johnston's for Robert Newhouse's.  And Anderson did little with the handful of short yardage carries he received.  He's not bad, but it's not that difficult to find better.

Dallas currently has five picks in the 4th, 5th and 6th rounds.  That total will likely rise by two when supplemental picks are awarded.  For those reasons, I strongly suspect Dallas will select one of Johnson, Fiammetta or Georgia's Brannan Southerland somewhere in the late 4th or in the 5th round.