Alabama With a clean out of some premium college talent this season, every team will have vacancies with the next stars hoping to shine through.

But what will be the most important battles for 2013?

I'm excluding the lesser teams here, I'm looking at teams who have a shot at a BCS game, or at least the bigger conference titles.

Also, it's mostly quarterbacks and running backs, but there's enough variety to please some people.

Alabama - Offensive Line

Some may point to the sterling play of quarterback AJ McCarron or the power running of Eddie Lacy and TJ Yeldon, but this offense wouldn't have been as successful without the five men up front.

Now, they have to replace their three best players on that unit. LG Chance Warmack, C Barrett Jones and RT DJ Fluker (the only underclassman) will be on NFL rosters next season. Head coach Nick Saban has recruited well, but who will replace these multi-year starters and All-Americans? 

Clemson - Running Back

Andre Ellington (1,081 yds, 8 TDs) may have taken a back seat to the Tajh Boyd show this season, but he was a key component of the Tigers' offense and often came through when the rest of the offense was misfiring (such as the Auburn game).

Roderick McDowell ran for 450 yards and 5 scores as a reserve and will probably get the starting nod at the beginning of spring, but don't write off any of the other talented backs on the roster. Keep an eye out for incoming freshman Tyshon Dye, who provides a nice blend of speed and power.

Florida State - Quarterback

EJ Manuel steadily got better over his career in Tallahassee, but now he's off to try his has hand in the NFL. Who replaces him will be the key to the Seminoles ACC chances next season.

Clint Trickett has shown some ability as Manuel's backup the last couple of years and has even won a couple of games, but he's still pretty green. Jacob Coker also saw time in mop-up duty, but Trickett is by far the most experienced on the roster, something that could become an issue in the Seminoles' hunt for another ACC title.

Kansas State - Quarterback

On paper, Klein may not seem to be such a hard act to follow. He was a fine athlete and had nice production, but there are better guys out there. Well, Klein willed this good, but not great (talent-wise) team to 21 victories and a Big 12 championship over the last two years.

He's considered to be Tebow-lite, which is lofty praise (depending on who you here it from), so who has the thankless job of taking his place? Athletic Daniel Sams is the heir apparent, having backed up Klein this season and seeing some action, but watch out for recent JUCO-signee Jake Waters, one of the top pocket passers at the junior college level for 2013.

Michigan State - Running Back

Yeah, Michigan State's defense was really, really good, but their offense was really, really bad. That is, except for this guy - Le'Veon Bell. Last season he ran for 1793 yards and 12 TDs on a huge 382 carries, over 90 percent of his teams rushing production, and almost single-handedly (he got a little help from his O-line) won games for the Spartans.

In the interest of self-preservation, he jumped ship to the NFL, leaving a 242-pound hole in the offense. The good news is, the defense will still be really, really good, while the passing attack should a step forward as the young guys are more experienced, but who takes Bell's spot?

His "backup", Larry Caper is out of eligibility, so someone untested has to shine through. Nick Hill was the third rusher, but had just 21 carries for 61 yards, while Nico Palezeti and Trevon Pendleton played mostly on special teams. The incoming freshman class doesn't appear to provide instant help, so the running game could be a problem for a Big Ten contender.

Manti Notre Dame - Linebacker

Apart from Klein, no other individual player had as big an impact on his team as Manti Te'o.

The national championship game and the bizarre Deadspin story have since cast a negative light on the Fighting Irish linebacker, but no one can take away from the impact he had on his team.

Not only did he make his teammates better, but he came up with big plays at critical junctures in games, and that cannot be coached.

His poor performance in the title obviously has some extenuating circumstances, and it may cost him some cash in the Draft, but Brian Kelly and Notre Dame know how hard he will be to replace.

There is plenty of talent on board, but athleticism is not the issue. Where will ND find a leader of the caliber of Te'o when the 2013 season kicks off. Start watching in spring camp.

Ohio State - Defensive Line

The Buckeyes aren't just losing a player or two, they're losing all four starters in an exodus akin to Alabama's offensive line. Only Jonathan Hankins is a junior, so it's not like there was much choice, but Hankins, John Simon, Nathan Williams and Garrett Goebel are all multi-year starters and their experience will be hard to replace.

This is Ohio State, so there is talent to burn, but finding four players to step up and perform at the level of a unit that worked together for two years is high expectation indeed.

Sophomores Michael Bennett and Steve Miller, among others, saw action last season with a view to building for this year, but a star has yet to shine from this bunch. 

Oklahoma - Quarterback

Landry Jones was not quite what the Sooner faithful had hoped for when he took over from Sam Bradford, but he was a good quarterback. Replacing him will be no easy task, especially with leading receiver Kenny Stills and Justin Brown moving on.

The man charged with taking over, at least as far as spring camp, is Blake Bell, who backed up Jones the last couple of seasons, although he only saw action in  mop up duty and as the Belldozer, the Sooners' short-yardage runner.

He can wing the ball around though, and will get the chance to strut his stuff soon. His athletic ability could come in useful too, as Jones was a statue, and Bell could open up the playbook some. Watch out for the some of the young talent waiting in the wings too. The job will be wide open.

Oklahoma State - Quarterback

This spot differs from the others on the list as the cowboys are not replacing a starter, they are trying to find one out of three who all played well last season.

Injuries meant OSU had to go through all three freshman QBs, and they still finished fourth in the country in total offense. JW Walsh is my favorite to start - he came back from a "season-ending" injury to play some down the stretch and brings a great blend of athleticism and passing ability - but Clint Chelf (another dual-threat) and Wes Lunt (more of a pocket passer) have shown they are good enough to get a long look in camp.

Unless someone lights things up from the beginning, expect to wait until August for head coach Mike Gundy to announce a starter.

Stanford - Running Back

Just like Le'Veon Bell, Stepfan Taylor was a tough runner who carried the offense with his ability to get yards out of nothing. Now, after three years of being the guy, the Cardinal will have to find someone else to replace their somewhat under-rated star.

The obvious choice would Anthony Wilkerson, a powerful now-senior runner who has shown he can get the job done on a limited basis in Stanford's power offense. Now he has to step up and expect 20-30 carries on a weekly basis and still produce.

Of course, there is one other option, although he is less suited to this particular style of attack. Barry Sanders Jr, who has a famous father, will be given every chance to at least earn carries in the offense this season.

By all accounts, he is somewhat reminiscent of his dad as a runner. Who wouldn't like to see that style grace our fields again?