D-linemen who could have been in San Francisco

As the NFL draft continues to creep closer, one mistake from last year's picks must still weigh heavily on the minds of San Francisco's front office.

In trading this year's top choice for what became offensive lineman Joe Staley, the 49ers wagered heavily in 2007 they wouldn't, once again, end up as one of the worst teams in the league.

Instead of protecting the team's future and insisting the traded pick be top-10 protected, Mike Nolan committed a fatal error and made a deal—with Bill Belichick.

We know how that turned out.

San Francisco entered the offseason with a historically bad offense and a defense that needs help up front.

Staley is a decent player, but he's not worth the seventh pick in 2008.

Instead of having that pick in a draft full of prospects on both lines, new general manager Scot McCloughan will pick have the 29th choice of the first round.

Ouch.

Just for kicks, let's take a quick look at a few of the defensive players the 49ers need but have no chance in selecting thanks to Nolan's blunder. We'll save the offensive guys for next week.

Vernon Gholston looks like the best player who should be available when the Patriots pick this year, creating a sort of irony. The same player who would fit well as an edge rusher in the 49ers' system will be chosen by their picking replacement. Too bad.

As the Giants showed in the Super Bowl, an elite pass rush is the key to stopping even the most potent passing attacks in the NFL. Gholston may not be a sure thing, but he did help the Ohio State Buckeyes reach two straight national championship games with one of the top defenses in America.

Over the past two years Gholston showed flashes of being great. In 2007 alone, he amassed school single-season (14) and single-game (four) sack records to go along with his 15.5 tackles for loss.

The second defensive lineman, one projected to be the eighth pick in the latest SI.com mock draft, is a Man of Troy with the talent to put him "up into top-four territory on some draft boards."

Sedrick Ellis, being a little undersized in height and weight, may be a better fit to play in a 4-3 system, but his 308-pound frame should allow him to play to the right or left of a strong nose tackle in the NFL and get pressure on the quarterback.

Overall, Ellis may be a reach at seven, and San Francisco would have preferred a shot at Gholston, but both players have more potential upside than what's been seen from Staley, a serviceable O-lineman.

Cornerback could also be a decent choice at seven, and speculation does have New England eyeing Leodis McKelvin from Troy, but the 49ers have no chance at him either.