The 30-year-old right-handed reliever on Friday received his visa in the Dominican Republic, and he is scheduled to be at the Marlins' complex in Jupiter, Fla., on Monday.
Oviedo, formerly Leo Nunez, was placed on the restricted list last September when it was revealed that he was playing under a false identity. He returned then to the Dominican Republic, and it has taken months to resolve the matter.
Once removed from MLB's restricted list, Oviedo is expected to serve an eight-week suspension.
"I am very happy to get a U.S. visa this morning," Oviedo told the Dominican newspaper, Listin Diario. "I've decided to leave for Jupiter, Fla., next Monday. I wish to be with my mother on Mother's Day."
Mother's Day in the Dominican Republic is recognized on the last Sunday of May.
Oviedo will travel to the Marlins' complex in Jupiter, where he will begin working out. Because of the suspension, he won't be allowed to play in Minor League games until the final 15 days of his suspension.
Oviedo likely will pitch in simulated scrimmages.
"He's happy. He sent me a message," said Marlins reliever Edward Mujica, a close friend of Oviedo. "He told me, 'I got the visa already, bro.' I'm happy for him."