Undrafted out of Texas Tech in 2004, Wes Welker was signed by the San Diego Chargers, who released him shortly after, and he was able to carve out a niche as a backup Wide Receiver and Return Specialist with the Miami Dolphins. That itself would be a decent career for an undrafted player, but the New England Patriots (who are we kidding, Bill Belichick) traded for him, and he would become an elite wideout in the National Football League.
Becoming the favorite target of Tom Brady, Welker would rattle off five straight Pro Bowls and would lead the NFL in Receptions. A two-time First Team All-Pro, Welker would assist the Pats greatly in the playoffs, scoring four TDs, although he is one of the few Patriot stars of the modern era without a Super Bowl Ring.
Of note, Welker holds the record for the most seasons with 105 Receptions (5) and, as of this writing, is the all-time reception leader for the Patriots, no small feat indeed.
Steven Jackson is the all-time leading rusher for the Rams, passing no less than Eric Dickerson to do it. A model of consistency, Jackson recorded eight consecutive seasons in which he rushed for over 1,000 Yards, four of which saw him finish in the top ten overall, including a second-place finish in 2009.
2006 was actually a more productive season where the Running Back would finish with 1,528 Rushing Yards and another 806 in the air to give him 2,334 Yards from Scrimmage, the most in the National Football League that season.
With just over 15,000 Yards from Scrimmage over his career, Jackson might be worth a look as a preliminary nominee, but to make the Hall would be difficult despite how many Yards he accumulated.