Lochte's representative told USA Today in a statement the five-time gold medalist suffered a torn medial collateral ligament and a sprained anterior cruciate ligament in his left knee as a result of a "freak injury" Sunday in Gainesville, Fla.
The statement said a young female fan ran at Lochte, who caught her while the two tumbled over. The swimmer was injured when his knee hit a curb.
The girl was unharmed.
Lochte "will be taking a break from training and competition," it said. "His medical team expects him to make a full and speedy recovery and Ryan thanks everyone for their well wishes."
Lochte, a Florida native, has trained in Gainesville for much of his career.