Thompson was arrested Feb. 24 and charged with felony possession of marijuana and misdemeanor possession of drug paraphernalia, but the charges were dropped because of insufficient evidence against him.
"Deonte's clean," lawyer Huntley Johnson told The Sun. "I'm happy for him because I think it will make a big difference in his future."
Thompson has remained on the team after the arrest, as the Ravens said they would give themselves time to gather information and allow the legal process to play out. The Ravens have taken that same approach regarding the other recent arrests of running back
During the NFL owners meetings in Orlando last month, Head Coach John Harbaugh voiced support of his players while not condoning their actions.
"You can't be riding around in a car with marijuana in your bag," Harbaugh said. "I don't care what your reason or your excuse is for it."
Thompson, a 2012 undrafted prospect out of Florida, is entering his third NFL season. He has mostly been a reserve during his professional career, and last season he caught 10 passes for 96 yards. He is expected to compete for a roster spot heading into training camp this season.