Manning, a four-times most valuable player in the NFL who agreed to a five-year $90-million contract with the Colts last month, is expected to earn $23 million in total compensation for 2011.
In assessing payrolls based on figures from rotoworld.com, Bleacherreport.com and other published reports, Forbes said teams had especially poured money into quarterbacks and the defensive line.
Bradford, last year's first overall draft pick, was one of several young quarterbacks who benefited from lucrative deals signed before the recent lockout which resulted in a rookie wage scale as part of a new collective bargaining agreement.
The league and its players finally ended their bitter row over how to carve up their financial empire last month after a four-and-a-half-month lockout.
The five highest-paid NFL players for 2011:
1. Peyton Manning, Indianapolis, quarterback, $23 million
2. Sam Bradford, St. Louis, quarterback, $18.4 million
3. Tom Brady, New England, quarterback, $18 million
4. Michael Vick, Philadelphia, quarterback, $15.9 million
5. Richard Seymour, Oakland, defensive lineman, $15 million
(Writing by Mark Lamport-Stokes; Editing by Frank Pingue)