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Every school in America must deal with graduations, transfers, and early entries to some degree. A handful of programs, however, are reeling at the prospect of rebuilding from the ground up, cobbling together new units that have been ravaged by departures.

Florida is still one of the favorites to win the SEC, but what happens to the defense if the new ensemble of linebackers isn't ready to handle the pressure? And while Iowa is gearing up for another run toward a BCS bowl game, it'll be forced to adjust expectations if the new offensive line doesn't gel between now and the Sept. 4 opener with Eastern Illinois.

Everyone loses players, but when an entire unit takes a beating, it's up to the staff and the holdovers to limit the damage and make a smooth landing. An inability to do so in the offseason could linger when the games count in the fall.

10. Miami running backs While everyone in the program knew Javarris James would be out of eligibility in 2010, no one could have guessed Graig Cooper would be unavailable as well. Cooper, the presumed workhorse this season, suffered a devastating knee injury in the Champs Sports Bowl and is expected to be sidelined for the entire year. Former safety Damien Berry could be in store for a breakthrough final season after rushing for 616 yards and eight touchdowns on only 93 carries. The vacancy should also create more playing time for Mike James, the 5-11, 220-pound pinball out of last year's recruiting class. After playing sparingly as a rookie, he'll be asked to gradually increase his snaps and give occasional breathers to Berry.

9. Kansas passing game First-year head coach Turner Gill will experience a one-two body blow when he begins to coordinate his passing attack for this season. Not only do the Jayhawks lose all-time leading passer Todd Reesing, but also top receivers Dezmon Briscoe and Kerry Meier, who combined for 186 grabs a year ago. Taking over for Reesing will either be Kale Pick or junior-college transfer Quinn Mecham. Whoever wins the job will spend plenty of time looking for Johnathan Wilson and Bradley McDougald, outstanding compliments from a year ago. Beyond just determining a workable depth chart in the spring, Kansas plans to spend the next few months simply getting the quarterbacks and receivers on the same page.

8. Texas O-Line Although the 'Horns haven't lost any All-American types, it's never easy replacing the left side of the line and rock-solid C Chris Hall. The right side will be set with Michael Huey and Kyle Hix, but three new regulars must be found and overall depth will have to be built back up. Junior David Snow is expected to fill the void at the pivot, and there's hope that young Mason Walters can make it back from foot surgery in time to fill the opening at guard. The battle to replace Adam Ulatoski at left tackle could be far more interesting. One possibility is senior Tray Allen, the blue-chipper from 2007, who's yet to approach his high school hype.

7. Ohio State D-Line

While many schools would love to have the Buckeyes' problem up front, it will have a different look from 2009 and require some younger kids to step up. The good news is that DE Cameron Heyward put off the NFL Draft for another year and DT Dexter Larimore is a returning starter. The concern? Talented ends Thaddeus Gibson and Lawrence Wilson, and veteran tackles Doug Worthington, Todd Denlinger and Robert Rose are no longer in Columbus. On the outside, relentless Nathan Williams is poised for a starring role after making 26 tackles, eight tackles for loss, and 3.5 sacks. On the inside, John Simon will be bucking for a promotion after earning a spot in the rotation as a rookie last fall.

6. Alabama linebackers Sure, everyone knows that All-American Rolando McClain left early for the NFL Draft, but he's not the only Tide linebacker who needs to be replaced. Eryk Anders was consistently one of the team's most underrated players and Cory Reamer was solid at strongside. 'Bama is capable of regrouping in a hurry, especially if Dont'a Hightower makes a successful return from last year's knee injury. The silver lining of his absence was that it opened the gate for true freshman Nico Johnson to get on the field, which will really begin paying dividends in 2010. The favorite to complete the starting lineup at Anders' old spot is Courtney Upshaw, a physical run stopper, with 15 tackles on the 2009 resume.

5. Florida linebackers No the sky isn't falling over Gainesville, but you certainly don't get better by losing an All-American and three of your top five tacklers, all linebackers. Now that Brandon Spikes, Ryan Stamper, and Dustin Doe are out of eligibility, it opens the door for a whole new wave of budding defenders to make plays. A.J. Jones and Brandon Hicks are the vets, but both could get pushed to the back page by underclassmen, such as Jelani Jenkins and Jonathan Bostic. No matter who's in the lineup, Florida will have no problem putting a ton of speed and athleticism on the field at all times.

4. Virginia Tech D Bud Foster is one of the game's top defensive coordinators. And he'll get ample opportunity to prove it this season. The Hokies will be missing a slew of key seniors, including three starting defensive linemen, three starting defensive backs, and LB Cody Grimm, last year's leader in tackles and tackles for loss. The foundation will come from three seniors, DT John Graves, S Davon Morgan, and CB Rashad Carmichael, and junior linebackers Jake Johnson and Barquell Rivers. After that, however, the competition will be ferocious, especially at defensive end and cornerback. Foster will need to be expeditious since Boise State is headed East for Labor Day.

3. Iowa O-Line The Hawkeyes had four All-Big Ten linemen on last year's 11-win squad. The Hawkeyes also have four All-Big Ten linemen to replace, C Rafael Eubanks, G Dace Richardson, and tackles Bryan Bulaga and Kyle Calloway. Oh, and veteran guards Dan Doering and Andy Kuempel are also gone. Few schools do a better job of coaching up blockers than Iowa, a track record which will be tested this fall. Could this line be built around Riley Reiff, who was just a redshirt freshman a year ago? He has a great future and performed well when Bulaga was hurt. He'll be joined in the lineup by Julian Vandervelde, but after that, it'll be a free-for-all among six returning letterwinners and five redshirt freshman.

2. Penn State linebackers The troubling news in Happy Valley is that the defense has lost three all-star linebackers to the NFL, Sean Lee, Navorro Bowman and Josh Hull. However, at Linebacker U., they don't blink at the prospect of replenishing at this unit. Chris Colasanti, Bani Gbadyu and Nate Stupar are returning letterwinners, with first dibs on filling the three openings. Oh, and do not forget the name of sophomore Michael Mauti. He was on the tarmac and preparing to launch before suffering a season-ending knee surgery in the summer. It could take a while before Penn State regroups, but it'll eventually get there.

1. USC secondary This is like a jail break if all of the prisoners were future NFL defensive backs. The Trojans must replace all four starters, each an All-Pac-10 selection from a year ago. Although the biggest void is left by All-American S Taylor Mays, it won't be easy without Kevin Thomas, Josh Pinkard or Will Harris either. After CB Shareece Wright, who missed the regular season due to academic reasons, USC will have to rely heavily on Pete Carroll's recruiting from the past few seasons. At safety, T.J. McDonald, Drew McAllister, and Jawanza Starling are poised for promotions. The battle to start opposite Wright could revolve around T.J. Bryant and Byron Moore.