The five-time Olympic champion tore a ligament and sprained another in his left knee last weekend during a visit to Gainesville, Fla.
A teenage girl ran at Lochte, who tried to catch her, but the two fell over in the process, his publicist said. Lochte hit his knee on a curb, while the girl was not hurt Sunday.
Publicist Janice Lee says in a statement issued Tuesday that Lochte's medical team expects him "to make a full and speedy recovery."
Lochte tweeted that he was headed to Gainesville last weekend. He trained there for several years after competing for the University of Florida. He has moved his training to Charlotte, N.C.
Lochte is next scheduled to represent the U.S. in the Duel in the Pool meet in Scotland on Dec. 20-21.