DeSean Jackson says his former agent Drew Rosenhaus violated NFL Player's Association rules by bribing him to sign with his agency back in 2009 with truckloads of cash and a Louis Vuitton bag ... this according to legal docs obtained by TMZ Sports.
Jackson filed new court papers in an effort to overturn an arbitrator's ruling that he owes Rosenhaus more than $500k for failing to repay loans.

In the docs, DeSean says he shouldn't have to pay Drew a dime because a huge chunk of the cash was given to him to induce DeSean to use D.R. in his next contract negotiation.