Rick Pitino: I've Done Nothing Wrong No Evidence Against Me!

Rick Pitino says there's not a SHRED of evidence proving he did anything wrong to justify his firing -- and has lawyered up in what seems to be a prelude to a legal war with Louisville.

As we previously reported, the University of Louisville says it put Pitino on "unpaid administrative leave" in the wake of an FBI probe of an Adidas exec, who was allegedly bribing recruits to attend Adidas sponsored schools, including UL.

While Pitino hasn't been formally accused of a crime -- and no other Louisville staffer has been accused either -- the school took action anyway ... and Rick is pissed.

"Coach Pitino has done nothing wrong and there is no evidence to suggest otherwise," his attorneys said in…