4-3 teams emphasize speed, not size, at linebacker

A comparison of Pro Bowl rosters shows 4-3 linebackers declined in average weight from roughly 248 pounds to 240 since 2001. The average weights declined slightly every season during that span, except for 2004.

While 3-4 defenses have proliferated, taking with them bigger linebackers, the league's 4-3 linebackers are all about speed -- for good reason.

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Listed at 223 pounds, Denver Broncos linebacker Ian Gold takes on 245-pound Cleveland Browns running back Jamal Lewis.

Fewer offenses lean heavily on powerful fullbacks. Defenses are less likely to need bruising linebackers to combat them.

Athletic tight ends are becoming more common. Heavier linebackers have a harder time covering them.

Teams are more likely to run and pass from spread formations on first and second downs. Most linebackers weighing 250 pounds have a harder time matching up.

"If you've got a couple of big defensive tackles who can pick up blocks, you can free up those [small] linebackers," Mora said. "Denver is a great example. They put a premium on speed at linebacker."

The Broncos list linebacker Ian Gold at 223 pounds and safety John Lynch at 220.

Coaches still talk about running the ball and stopping the run, as they should, but the smart ones know winning teams are more likely to excel in a range of offensive stats, notably yards per pass attempt.

Trotter was long a mainstay of the Eagles' defense. He was a four-time Pro Bowl choice and respected in the locker room. But he was also increasingly a situational run stuffer, and coaches preferred Gaither's potential.

If Trotter fails to resurface as a starter -- he reached a one-year deal with Tampa Bay on Monday -- the league could be down to eight starting 4-3 linebackers listed at 250 or heavier.