Simon has been detained for 49 days following the shooting death of his cousin on New Year's Eve in the town of Luperon. Another man was injured during the celebration.
Phil Isaac of the Para Sports Group said a ballistics test proved that the bullet that killed Michael Esteban Castillo Almonte, 25, didn't come from the gun Simon turned into authorities.
At this point, there doesn't appear to be any other evidence.
"We met with the government attorneys there and they have no evidence against Alfredo that can substantiate their case," Isaac said. "They essentially agreed to release him because they have no case."
Though he's been jailed, Simon has never been formally charged with a crime.
Simon's attorneys will file another appeal on Wednesday, at which point Simon could be released.
The Orioles placed Simon on the restricted list on Friday to free up a spot for Vladimir Guerrero on the 40-man roster. He won't be paid or accrue service time.
Even if Simon is released from jail this week, he could be facing a two-to-three week process to obtain his visa, so he's a long way from Sarasota and a return to the 40-man.
Simon hasn't done any throwing since being detained, but Isaac said the reliever has been running and working out.
The Orioles continue to decline comment because Simon hasn't been charged with a crime.