It has become one of the most over-drafted and productive positions from which to select, and expectations are that trend will continue this year.

As many as six offensive tackles could be selected in the first round of this month’s NFL draft; 16 tackles were selected in the first round of the previous three drafts.

At the root of this frenzy for tackles is the need to protect the quarterback. A survey of starting left tackles, in particular, reveals a major emphasis on needing to find that player early in the draft. He is a premium-position player – maybe the second-most important man on the team – and tackles big enough and agile enough to take on the game’s premier pass-rushers are low in supply and high in demand.

As Packers General Manager Ted Thompson – most general managers, for that matter – are fond of saying: “You can never have enough big guys.”

The “big guys” in this draft are led by Nate Solder of Colorado, Tyron Smith of USC, Anthony Castonzo of Boston College and Gabe Carimi of Wisconsin. They are each considered locks to be selected in the first round. Derek Sherrod of Mississippi State and James Carpenter of Alabama, a fast-rising prospect that may play guard in the NFL, may slip into the bottom of the first round.

Falloff? Not yet. Marcus Gilbert of Florida, James Brewer of Indiana, Joseph Barksdale of LSU, Chris Hairston of Clemson and Jason Pinkston of Pitt all have starter potential.

Solder has ridden a sensational combine to the top of the class. Smith declined to work out at the combine but is regarded as a top athlete with a high ceiling. Castonzo is a product of an assembly-line program for offensive linemen. Carimi built his reputation by dominating the competition in the Big Ten, which boasts defensive linemen Cameron Heyward and Ryan Kerrigan.

Sherrod took his game to a much higher level last season. Carpenter is a good swing man for a team that wants to run the ball. Gilbert has all the tools but is coming off a subpar season that has dropped his stock. Barksdale is a road-grader. Pinkston is a pure pass-blocker.

Florida’s Mike Pouncey and Penn State’s Stefen Wisniewski are this year’s bloodlines picks at guard. Pouncey is thought to have moved into the first round and Wisniewski probably isn’t far behind. The crop of guards also includes Danny Watkins of Baylor, Marcus Cannon of TCU and Rodney Hudson of Florida State, all of whom could be off the board by the end of the second round.

The talent at guard won’t fall off until after Wisconsin’s John Moffitt and UConn’s Zach Hurd are off the board.

Center, however, is another matter. After a couple of years that produced three centers selected in the first round, this year’s crop is thin at the top but offers depth in the middle rounds. The possibility also exists that Wisniewski might project as a center at the next level.

Missouri’s Tim Barnes and Cincinnati’s Jason Kelce top the center class, but neither is likely to go off the board before the third round.

When will the run begin on tackles? It’s become a familiar question in recent drafts. Its answer will determine how many are selected in the first two rounds of the draft because as soon as the first tackle is picked, panic will begin to set in. You gotta get the big guys early. It’s become a credo of personnel directors.

Vic Ketchman is a veteran of 39 NFL seasons and has covered the Steelers and Jaguars prior to coming to Green Bay.