ESPN NFL

Mamas, don't let your babies grow up to be fullbacks. There isn't a great future in the position in the NFL.

Fullbacks are warriors. Their jobs involve the ultimate sacrifice. Basically playing for the NFL minimum, fullbacks sacrifice their bodies for the good of the running game. Many operate under one-year contracts. Most come out of the season with injuries that shorten their careers. Still, there is nothing more beautiful to watch in football than a fullback crashing into a linebacker and knocking him backwards.

But the position is in trouble. A few years ago, fullbacks seemed to weather a storm of change to three-receiver sets and multiple-tight end formations. But this year, a further erosion of the position is continuing. For those who play the positions, the trend is scary.

• Some teams are either eliminating the position from their active or 53-man roster. On Monday against the Redskins, the Cowboys deactivated fullback Lousaka Polite. The Vikings and Redskins replaced their fullback positions with H-backs and tight ends.

• More teams are trying defensive players as fullbacks in goal-line situations. The Jaguars have used defensive tackles Marcus Stroud or John Henderson. The 49ers are experimenting with nose tackle Anthony Adams. The Patriots are using defensive tackle Dan Klecko in many fullback-related situations.

Normally, fullbacks get between 35-53 percent of the offensive snaps, mostly in less-than-glamorous situations that include few carries and occasional pass receptions. But if fullbacks are losing time to tight ends and defensive players -- which they are -- you have to wonder about the future of the position.

"It's not like they have a conspiracy against fullbacks, but you are seeing a lot of different things out there," said 49ers fullback Fred Beasley, one of the best. "We're doing the same thing here using Anthony Adams on goal-line situations, but it's only on goal-line situations. I'm sure they are thinking that the big body will push some people, so you can run that big guy through."

But fullbacks should be scared. By my count, roughly 41 fullbacks populate 30 NFL teams, excluding the Redskins and Vikings. But the importance of the position seems to have been downgraded. Cory Schlesinger is a good fullback for the Lions, but he's out until midseason. The Lions didn't even replace him, preferring to go with more three-receiver sets. If they need a fullback, the Lions will use one of their two tight ends.

Injuries have taken their toll on some of the other fullbacks. Bryan Johnson of the Bears is on the physically unable to perform list and may eventually be active this season, so they are just patching the spot with veteran Marc Edwards. Richie Anderson of the Cowboys had to retire. Jon Ritchie of the Eagles was cut and hasn't found a new job.

"We get paid like the kicker, but I think teams need fullbacks," Beasley said. "To me, the fullback basically only has to touch the ball two or three times a game. That's maybe one carry and two catches. The rest of the time we are blocking. To me personally, that's my world. I love it. To be honest with you, I don't want the ball. I want to block. That's all I want to do. That's how I can bring a lot to an offense."

Beasley has been around since 1998, blocking and sacrificing his body, and he realizes he's fortunate to have spent his career with the 49ers. Bill Walsh developed the West Coast offense in San Francisco, and despite coaching changes, the 49ers still run the West Coast, which probably values the fullback more than most offenses.

"That's why I'm trying to hold on here as a 49er," Beasley said. "I think in the West Coast offense, the fullback is just as important as an offensive lineman. We're involved in pass protection and help protect the quarterback. But you realize, it's all depends on who you have as an offensive coordinator."

The veteran fullbacks should have some staying power over the next couple of years because it's becoming harder and harder to find proven players at the position. Colleges aren't using them thanks to the widespread use of spread offenses. While three-, four- and five-receiver sets have helped to develop quarterbacks that are ready to run NFL offenses, college offenses aren't churning out fullbacks.

Only four fullbacks were drafted in 2005, and none are playing. One, Rich Razzano of the Bucs, was suspended for four games for steroids. It's probably good news for the established fullbacks that the youth pool of replacements isn't there. But that also means that teams will adapt and find ways to work without an actual fullback.

Teams are being forced to be creative. They are converting undrafted linebackers into fullbacks. But creativity could be dangerous to fullbacks. Salary caps and 45-man active rosters always have coaches looking for more ways to utilize talent. If they can find a tight end or linebacker who can also play fullback, that gives them more roster flexibility.

Bill Belichick is the master of versatility, and Klecko is evolving into a multi-use player. Other coaches might try to copy that model.

And if the college ranks are producing only four draftable fullbacks a year, it's only natural for scouts to start looking for different options. Why not try to find a fifth linebacker who can switch over to be a third tight end and a full-time fullback?

Roster spots are precious. Teams are becoming less reliant on fullbacks. It's not out of the question that three or four years from now there might be fewer than 35 fullbacks on NFL rosters. West Coast offenses will have them. Others might not.

John Clayton is a senior writer for ESPN.com.