No. 1 WRs becoming endangered species

Whether it was because of age or inconsistency, the four NFC East teams looked long and hard this offseason for new options at wide receiver.

The Eagles eternally seem to be looking for a No. 1 receiver. The Giants were looking because Amani Toomer is 33 and Plaxico Burress is 30. Cowboys owner Jerry Jones unsuccessfully made trade calls for Chad Johnson, Anquan Boldin, Roy Williams and Larry Fitzgerald. The Redskins also inquired about Johnson. In the end, the only options were in the draft.

What's becoming a No. 1 problem for teams is their inability to find new No. 1 receivers. Over the past six seasons, only six Pro Bowl receivers have been developed. That's an amazingly low number.

Teams have tried. An average of 32.8 receivers were drafted each year since 2001, but only 26 -- 27 if you consider Anthony Gonzalez of Indianapolis in the three-receiver set -- are currently on depth charts as starters for teams that drafted them. That's less than one per team. Thirteen post-2001 draft choices ended up going to different teams to start.

Fitzgerald, Boldin and Williams represent half of the six Pro Bowl receivers developed since 2001, which explains why they were the targets of teams in need of No. 1 threats. The Cardinals gave Fitzgerald a four-year, $40 million contract in March. Williams is in the final year of his contract, and if the Lions don't think he's worth Fitzgerald money, he might be franchised and traded next year. The Cowboys and Eagles will be waiting.

As tough as it is to find starting quarterbacks, the search for new receivers is growing tougher and tougher. Some general managers are starting to think it's tougher to find top receivers than quarterbacks, which seems incredible, considering how much more passing there is on the college level.

The reasons are simple. The jump from college to the pros for receivers is one of the toughest for any position. ESPN analyst Cris Carter explained it well last week on "NFL Live." In college, an opposing team may have only one good cornerback, so all the pro prospect receiver needs to do is slide to the other side of the field and run his route virtually unchallenged.

In the pros, most of the corners are talented enough to match up and make life difficult. Carter cited three problems facing young receivers. First, they have to learn how to beat man defenses, which he estimates a receiver will see 70 percent of the time. To do that, Carter said receivers have to learn to use their hands to fight their way off the line of scrimmage to get past a pressing corner. It takes a lot of time to learn that skill.

Second, the receiver must learn the routes and learn the defenses. Many receivers, Carter said, don't recognize a Cover 2 or Cover 3, or understand where to "sit'' in an area to catch the ball. Carter used the curl route as an example: Although a coach might devise it as a 14-yard route, the smart receiver will pick up the coverage and be ready to "sit'' in the zone to catch it at 11 or 12 yards.

Finally, Carter said great receivers need to be special. They have to do special things, like run after the catch, make great receptions and score touchdowns. Many don't end up being special.

The biggest problem facing teams is that too many college receivers are turning pro too early, and it's screwing up the drafts. Normally, six or seven underclassmen turn pro as wide receivers. Many fail. Forty underclassman receivers turned pro from 2002 to 2007. The long list of receivers no longer with the teams that drafted them includes Ashley Lelie, Jabar Gaffney, Antonio Bryant, Reche Caldwell, Shaun McDonald, Kelley Washington, Charles Rogers, Brandon Lloyd, Devard Darling and Chris Henry.

As a result, teams have become more cautious in selecting receivers who skip their senior seasons. In 2006, Santonio Holmes of the Steelers -- an underclassman -- was the only receiver taken in the first round, and he didn't go until the 25th pick. This year, no receiver went in the first round, something that hasn't happened since 1990. However, six of the 10 receivers picked in the second round were underclassmen.

Teams in need of receivers are being forced to resurrect the careers of older players. The 49ers signed Isaac Bruce. The Panthers and Bears went back to their pasts for former success stories -- Muhsin Muhammad (Panthers) and Marty Booker (Bears).

Of the 22 Pro Bowl receivers currently starting, 12 are in their 30s. Reggie Wayne of the Colts, Chris Chambers of the Chargers and Steve Smith of the Panthers turn 30 this fall. Santana Moss of the Redskins turned 29 over the weekend.

The next wave of potential Pro Bowl receivers isn't bad. There just aren't enough of them. Lee Evans of the Bills, Roddy White of the Falcons, Marques Colston of the Saints, Greg Jennings of the Packers, Brandon Marshall of the Broncos and Jerricho Cotchery of the Jets are young receivers knocking on the Pro Bowl door. Dwayne Bowe of the Chiefs caught 70 passes as a rookie.

The good news is the older receivers aren't over the hill yet. The bad news is not many replacements are seen on the horizon.

John Clayton, a member of the Pro Football Hall of Fame writers' wing, is a senior writer for ESPN.com.