Siani signed a minor-league contract with the Tigers on Friday, Emily Waldon of Baseball America reports.
Siani was released by the Orioles on Aug. 4 but will now receive an opportunity to carve out a role for himself in the Tigers organization. However, the 27-year-old outfielder has slashed just .178/.294/.256 across 214 plate appearances in Triple-A this year and isn't likely to offer anything more than organizational depth.