Cash Money Sports is officially in business -- TMZ Sports has  learned the agency has just signed its first high profile athlete ...  Texas A&M wide receiver Mike Evans. Evans -- considered one of the  best players in the upcoming NFL Draft -- had initially hired another  agency to rep him ... but we're told Evans has now signed on the dotted  line with Cash Money. FYI -- Cash Money is run by Bryan "Birdman"  Williams and Ronald "Slim" Williams -- the brothers who built the Cash  Money record empire ... the home of Drake, Lil Wayne, Nicki Minaj and  Paris Hilton. What's interesting ... Evans is tight with Johnny Manziel  ... who happens to be BFFs with Cash Money rapper Drake. So, the  question ... will Johnny follow his wide receiver to Cash Money  Sports? The arrival of Cash Money Sports could set up a battle royale  between CMS and Jay Z's Roc Nation Sports agency. 6:35 PM PT -- Sources  tell us ... Cash Money Sports will be working with Priority Sports --  the agency Evans initially signed with -- in some capacity, but the  details of the relationship are unclear.  //