The 6-foot-6 forward is the 32nd-ranked prospect on next year's ESPN 100.
Hopkins originally committed to Louisville in November but says the NCAA's notice of allegations against the Cardinals forced him to reconsider his decision.
"I opened up my recruitment because there were a lot of uncertainties on what is going on with the sanctions," Hopkins told 247Sports' Brian Snow. "They also keep appealing (the sanctions), which is only making it harder on me."
Hopkins' decommitment makes point guard Bobby Pettiford the school's lone top-100 2021 recruit.