Tip Sheet: Revolving door up front

5/23/2010 - NFL New York Jets
Richard C. Lewis/Icon SMI

When the New York Jets released six-time Pro Bowl blocker Alan Faneca last month and plugged in rookie second-rounder Vlad Ducasse as his replacement at left guard, it essentially ended one of the more compelling streaks in recent NFL history.

The Jets had started the same five players on the offensive line -- left tackle D'Brickashaw Ferguson, center Nick Mangold, right guard Brandon Moore, right tackle Damien Woody and Faneca -- for 35 straight games, counting the playoffs last season. And although that consistency might not have seemed like much of a feat 25 or 30 years ago, it qualifies as an eternity now.

"You just don't see it these days," said Bill Callahan, the Jets' assistant head coach for the offensive line. "Once, it was just about the norm … but not anymore."

In fact, the Jets were the only NFL team to start the same five offensive linemen for every game in 2009. The destabilization of offensive line units, where players once stayed together for several seasons, is an unfortunate trend around the league. And it's one that was evident last season.

Nearly half the teams, 14 of 32, used five or more different starting quintets in '09, and 11 franchises employed at least eight starters each. The average for the league was 4.2 different starting combinations and 7.4 starters. Buffalo, which finished 6-10 and was ranked No. 30 in overall offense, used the most combinations (nine) and the most starters (11).

The only other franchises with double-digit starters were Oakland and Seattle, with 10 each. Not surprisingly, the Bills, Raiders and Seahawks finished the 2009 season with an aggregate record of 16-32.

That's a lot of shuffling on a unit that once represented a bedrock of consistency.

Once upon a time, an offensive line coach could pencil in his starting five and count on the same group lining up every week, and perhaps from year to year. Former Bills offensive line coach Jim McNally, who spent 14 seasons tutoring blockers, noted a few years ago that one could review a bunch of team pictures and "notice that the offensive linemen were the same four, five, six years in a row … and were basically in the same places in the picture."

Those days have been gone for several years, and the dearth of offensive line stability has been magnified by the era of free agency. Clearly, attrition accounts for some of the changes. But for all the punishment they absorb, offensive linemen tend to have long careers. Instead, the mobility created by free agency, and the spiraling contract averages that have resulted, prompted many of the switches. Since free agency began in 1993, teams have averaged 1.75 new starters per year. Until three years ago, the average was 2.1.

Most coaches and players surveyed this week agreed that, although athletes are better now on the line, overall offensive line play has waned. More than any other unit, an offensive line demands cohesiveness. But rarely do the same five players stay together long enough to achieve the necessary mesh.

"You'd like to be able to look to either side of you and see the same guys every week," said Detroit center Dominic Raiola, who started all 16 games for the Lions. "But that hasn't been the case for us. … I think you see effects around the league."

The Lions started three different players at both guard spots in 2009.

The revolving door on offensive line play was so prevalent in 2009 that it really didn't play favorites, affecting playoff teams and non-postseason clubs as well. The 12 playoff franchises averaged 4.0 different starting combinations and 6.8 starters, not significantly better than the leaguewide standard. For the top 10 clubs in total offense, the averages were 3.8 and 6.9, and only three of those teams employed fewer than three starting quintets.

Two of the six clubs that used one or two starting line units, Pittsburgh and Tampa Bay, failed to make the playoffs.

By far, the most stable position along the offensive line in 2009 was the center spot. Twenty-six centers started all 16 games for their respective franchises. The most itinerant position was right tackle, where teams used an average of 1.9 starters.

Len Pasquarelli, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com.