Joe Mixon's agent wants fans in Cincinnati -- and around the NFL -- to give the newly drafted Bengals running back a chance to prove he's a great person. TMZ Sports asked Mixon's agent, Peter Schaffer, about his message to Bengals fans after the team drafted the embattled star running back in the 2nd round this weekend. "Give the young man a chance," Schaffer tells us, "to prove he can be a great member of the community." Schaffer says 'cause his road to the NFL has been so bumpy, Mixon felt "pure childlike joy" when he heard his named called Friday night ... while family that surrounded him cried. As for what Mixon's gonna do on the field, Schaffer -- who once repped HOFer Barry Sanders -- says JM has every bit the ability that #20 had when he entered the league.