Points to notice:
- Harvey Specter was clearly impressed by Mike Ross' ability.
- Mike Ross wanted to get out of criminal activity.
- Mike Ross stated that he always wanted to be a lawyer, but he was disbarred from Harvard Law School as he was caught writing exam for someone else (Trevors suggestion so he could make extra money as he was poor) he couldn't pursue it.
Hence, he could have given an offer to Mike, that since he needed to hire someone exceptional who Mike is, that he would pay for his tuition and in return when he gets his degree Mike would have to work for him. This way Mike gets a degree and Harvey has hired an associate, for future.
We know Jessica paid for Harvey's Law education, so Harvey could have done the same.
Why didn't Harvey sent Mike to complete his education?