Why are there first-round DE predictions for the Titans?

There are more mock drafts on the web than you can shake a stick at and for obvious reasons I view some as being more realistic and credible than others.
Many of the mocks are predicting the Titans will select a defensive end in the first round of the draft this year. While I understand why many of them have done that, it does make me wonder why some of the more reputable draftniks have also done so.
2009 is the last year on the contracts of Jevon Kearse and Kyle Vanden Bosch, so it’s not surprising that some of the mocks are projecting a DE selection by Tennessee at #30. My reaction to that is the people making those predictions haven’t done their homework.
They apparently aren’t aware of the quality depth behind The Freak and KVB. Jacob Ford and David Ball both performed solidly as backups in 2008. William Hayes began the season as a very raw player but gained valuable experience which will help the Titans down the road.

What puzzles me is why some of the better prognosticators aren’t taking that into consideration.
At least six different DEs have been forecasted to be the Titans’ first round selection. These are the ones I’m aware of:

Robert Ayers, Tennessee
Everette Brown, Florida State

Michael Johnson, Georgia Tech
Paul Kruger, Utah
Aaron Maybin, Penn State
Incidentally, only one of those guys seems to be a typical 4-3 DE. Most of the rest look like tweeners between a 4-3 DE and 3-4 OLB. One, Jackson, appears to be a 3-4 DE or 4-3 DT. But that’s another topic for another time.
Getting back to the point, why are so many mock drafts predicting Tennessee will go with a DE in the first round? I’d love to read your opinions on this.