Greenberg, who was hit in the head in his first Major League plate appearance in 2005 and struck out in one at-bat with the Marlins last season, signed a Minor League contract with the Orioles on Thursday.
"The opportunity is everything," Greenberg said. "That's all I ever asked for. I'm a baseball player. The media attention was great and it was a nice story, but the attention was to get the opportunity to showcase myself on the field, and I am so grateful that the Orioles are giving me the opportunity to be a part of their organization."
Greenberg, 31, was hit in the head while playing with the Cubs on July 9, 2005. The outfielder suffered a concussion, had vertigo and continues to have vision problems because of the incident.
He never made it back to the Majors until Oct. 2, when he pinch-hit for the Marlins against the Mets. He struck out swinging.
He has been with the Cubs, Dodgers, Royals, Angels and Marlins organizations in his career.