Here is part four of our preseason power rankings at each position.
We will update the power rankings each week during the regular season and release the final rankings for the season after the BCS title game.
The rating of a player and coach can fluctuate each week during the season depending on how they fared the previous week, but the power rankings measure overall career performances as well as their most recent results.
Here are the nation's top 20 offensive tackles. Next up: defensive ends.
OFFENSIVE TACKLE POWER RANKINGS
1. Gabe Carimi, Wisconsin (6-7/327, Sr.) BUZZ: The latest in a long line of dominant Badgers road-grading tackles, Carimi enters his fourth season as a starter after taking over for 2006 Outland Trophy winner Joe Thomas. Carimi could follow Thomas as an Outland winner and as a first-round pick.
2. Jason Pinkston, Pittsburgh (6-4/305, Sr.) BUZZ: Pinkston arrived at Pitt as a defensive tackle and wasn't switched to the offensive line until late in fall camp during his true freshman season; he became an immediate starter at right tackle but was injured in the middle of September and missed the rest of the season. He has been a full-time starter the past two seasons at left tackle and again will man the left side this fall.
3. Anthony Castonzo, Boston College (6-7/295, Sr.) BUZZ: He was the first BC true freshman offensive lineman in a decade to crack the starting lineup and has started every game since setting foot on campus. Castonzo began his career at right tackle and is entering his third season as the starting left tackle. He was a first-team All-ACC pick last season.
4. Marcus Cannon, TCU (6-5/350, Sr.) BUZZ: Some NFL scouts think Cannon is a better fit at guard in the pros, but regardless of position, he will be an early-round pick. He is massive and a dominant run-blocker, and he didn't allow a sack last season
5. Nate Solder, Colorado (6-9/300, Sr.) BUZZ: Originally a tight end, Solder has developed into an All-Big 12 tackle and one of the nation's best offensive linemen. He's big, smart (3.45 GPA in biology), strong (power cleans 400 pounds) and athletic (runs a 4.8 40 with - get this! - a 34-inch vertical jump).
6. Clint Boling, Georgia (6-5/315, Sr.) BUZZ: This fourth-year starter's versatility has made him one of the nation's more valuable linemen. He made six starts at right tackle, six more at left tackle and one at right guard last season on his way to earning second-team All-SEC honors. He's the best performer on a veteran Georgia line.
7. Matt Reynolds, BYU (6-6/322, Jr.) BUZZ: Reynolds returned from an LDS mission and took over as BYU's starting left tackle as a redshirt freshman in 2008; he has been a fixture ever since. Reynolds earned first-team All-Mountain West honors and also was an academic All-MWC selection last season. He has two older brothers, Lance and Dallas, who also played on BYU's offensive line. His younger brother, Houston, is a redshirt freshman lineman for the Cougars.
8. Lee Ziemba, Auburn (6-8/319, Sr.) BUZZ: Ziemba has made 38 consecutive starts over the past three seasons. He has earned second-team All-SEC honors from the league's coaches in each of the past two seasons. He recorded 67 knockdown blocks last season, when Auburn had one of the nation's most improved offenses.
9. DeMarcus Love, Arkansas (6-5/315, Sr.) BUZZ: Love, a former starting guard, moved to tackle last season and handled his new position with aplomb. He is one of four returning line starters for the Razorbacks.
10. Derek Sherrod, Mississippi State (6-6/305, Sr.) BUZZ: Sherrod has started at left tackle for the Bulldogs in each of the past two seasons. His efforts last season helped Mississippi State lead the SEC in rushing. Sherrod recorded 10 knockdowns and graded out at 90 percent against Kentucky to help Anthony Dixon rush for 252 yards in that game.
11. Chris Hairston, Clemson (6-7/325, Sr.) BUZZ: Hairston is Clemson's first player from Winston Salem, N.C., since wide receiver Perry Tuttle, a star on the 1981 national title team. The Tigers plucked another good one out of there in Hairston. He has excellent size and strength, and two of the Tigers' losses last season (to TCU and Maryland) came when Hairston was injured.
12. Michael Philipp, Oregon State (6-3/307, Soph.) BUZZ: Philipp doesn't have the prototypical height of an elite offensive tackle. But like his predecessor, Andy Levitre, Philipp proved you don't need to be 6 feet 6 to be a productive tackle. Philipp is a quick study who was the first true freshman to start on the offensive line at Oregon State since 1997.
13. Bo Thran, Oregon (6-5/281, Sr.) BUZZ: Thran moved from guard to left tackle last season and led one of the nation's top lines. The Ducks ranked sixth in the nation in rushing and tied for 10th in fewest sacks allowed. He is the best player on a line that returns all five starters.
14. Tanner Hawkinson, Kansas (6-6/293, Soph.) BUZZ: Hawkins was a tight end when he arrived on campus, but the Jayhawks needed him to play tackle. All he did at his new position was earn second-team Rivals.com Freshman All-America honors, starting all season at left tackle.
15. Marcus Gilbert, Florida (6-5/320, Sr.) BUZZ: Gilbert plays right tackle and protected the blindside for lefty Tim Tebow last season, and consistently earned high marks from his coaches. Gilbert played guard early in his career, but he's a much better fit at tackle. He played basketball and threw the shot in high school, and befitting someone who did that, he has quick feet and is nimble against speed rushers.
16. Adam Grant, Arizona (6-6/325, Sr.) BUZZ: Grant has recovered from injuries early in his career to lead one of the nation's underrated offensive lines. The former tight end is moving from right to left tackle this season.
17. Kenny Wiggins, Fresno State (6-7/315, Sr.) BUZZ: Along with standout guard Andrew Jackson and center Joe Bernardi, Wiggins plays on the best offensive line in the WAC. The unit paved the way for the nation's leading rusher, Ryan Mathews, last season. Wiggins is a big-time run blocker who might play guard in the NFL.
18. Kyle Hix, Texas (6-7/325, Sr.) BUZZ: Hix has started 28 consecutive games at right tackle. As with all Texas linemen, he needs to be moir?ggressive this season in the running game. Texas has changed its blocking schemes to get more push, and Hix should benefit.
19. James Carpenter, Alabama (6-5/300, Sr.) BUZZ: Carpenter arrived from junior college and immediately started at left tackle for the national champions. The Tide were fourth in the SEC in fewest sacks allowed, but his best work was in the running game, as the Tide rushed for 215 yards per game last season.
20. Rob McGill, Louisiana Tech (6-6/310, Sr.) BUZZ: McGill will be on the spot this season with the hiring of coach Sonny Dykes, who brings along a pass-happy offense. McGill earned All-WAC honors last season for an offense centered on running back Daniel Porter.