After Moss, free-agent WR class drops off quickly

Free agency begins on Friday, and if you are hoping for a big signing to save your favorite team's offense … well, you may have picked the wrong year. The 2008 free agents are a bit underwhelming, particularly at wide receiver -- with the exception of Randy Moss, who will probably be retained by the Patriots.

We're going to look at some of the top free-agent wide receivers using Football Outsiders similarity scores (explained here) to see what happened to players coming off similar three-year stretches. Similarity scores are missing a lot of information -- they don't consider the quality of a player's quarterback or teammates, for example -- but they do give us a good idea of what might happen to these players in the future.

The stats listed are receptions, yards and touchdowns, and each player is listed with his age in the next season following that stretch. Any numbers with an asterisk are prorated for the 1982 and 1987 strikes.

Berrian's comparables are a mixed bag of young receivers, some of whom became great second receivers (Keenan McCardell, Reggie Wayne) and some of whom were more run-of-the-mill second receivers (Gerald Carter, Justin McCareins, Michael Timpson). Porter isn't really someone you can use for a comparison; he only one catch the following year because he was feuding with his coach, not because he suddenly lost his talent.

The similarity scores here use actual numbers, but there's also a version that adjusts each receiver based on league-wide offensive trends. The predictive value isn't quite as accurate, but it is interesting to note that the most similar receiver to Berrian in that system is Henry Ellard from 1983-1985. Ellard, of course, blossomed into a Hall of Fame-caliber receiver with eight 1,000-yard seasons -- and like Berrian, he played his college ball at Fresno State.

Donte' Stallworth's impending breakout season has been impending so long that you may not realize how old he is. He was the first receiver chosen in that star-crossed 2002 draft that also brought us David Carr, Ryan Sims, and Wendell Bryant. 2008 will be his seventh season in the league.

The players on Stallworth's list of comparables didn't exactly light up the league during the remainder of their careers. Only Carrier and Conway played more than three additional years -- Booker will likely join them in 2008 -- and only Carrier and Conway managed a 750-yard season after the period in question. Over the next two seasons, these 10 players averaged just 454 receiving yards per year.

Hackett has been one of the most promising young receivers in the league for a couple years. Lam Jones is considered one of the greatest draft busts ever. Yet they had similar numbers from age 24 to 26. "Promising" numbers for a fifth-round pick aren't quite so promising from a guy who went second overall.

Fans are still waiting for Hackett to actually stay healthy for a whole season so he can fulfill that famed promise. The list of comparable players does not look hopeful. Jones never played again. Branch struggled with injuries after a strong 2005. Wilkins disappeared to the CFL. Guys like Pathon, Williams and Ferguson never had the breakout years they were hoping for. The upside for Hackett is probably not stardom, but instead a long career as a possession receiver, similar to Ike Hilliard. (Hilliard was much better than Hackett at 24, but very similar at 25 and 26.)

Most of Booker's comparables didn't have much of a career left. Pearson and Upchurch never played again, and Torrance Small retired with a nice new piece of jewelry after four catches with the 2001 Patriots. Bill Brooks had one more very good year in him, 763 yards and 11 touchdowns for the 1995 Bills. Of course, receivers seem to be lasting longer into their 30s in recent years, and the best-case scenario for Booker is that he becomes a chain-moving, first-down machine like Bobby Engram. Engram's best seasons have come in his 30s, including his first 1,000-yard season in 2007, at 34.

Randy Moss, New England

There are no historical players comparable to Moss. No other player in NFL history declined solely because he was playing football in a soul-sucking pit of despair (Oakland), and of course no other player ever caught 23 touchdown passes after escaping that pit. The most similar three-year career span -- using the word "similar" is quite a stretch here -- belongs to Muhsin Muhammad from 2002-2004, mostly because Muhammad managed 16 touchdown receptions in his fluky 2004 season.

Aaron Schatz is president of Football Outsiders Inc. and the lead author of Pro Football Prospectus 2007 and 2008.