Locksley was charged with driving while intoxicated, unlawful carrying of a weapon, marijuana possession and terroristic threat.
Smith will join as a redshirt junior with two years of eligibility remaining.
Battle's commit comes just one day after the Terps landed offensive tackle Santana Saunders.
Tyler DeSue and Max Bortenschlager were the starting quarterbacks.
“That one play just — it hurts,” Tyrrell Pigrome said. “Like, it still hurts.”
Richardson notched 41 tackles and one interception in 2018.