O'Leary, who played three seasons with the Buffalo Bills, was signed by the Dolphins to the practice squad on Sept. 18.
On Saturday, the Dolphins ruled defensive end Cameron Wake out. Wake, who has been dealing with a knee injury, will miss his first game since the 2015 season, when he suffered a torn Achilles.
Andre Branch, listed behind Wake on the depth chart, is questionable with a knee injury that forced him to miss last week's game. If Branch doesn't play, Charles Harris will likely make his third career start.
A sixth-round pick out of Florida State in 2015, O'Leary had 32 receptions for 473 yards and two touchdowns in 35 games for Buffalo, including 12 starts.
O'Leary, who is the grandson of golf legend Jack Nicklaus, was released by the Bills on Sept. 1.
The Dolphins also put quarterback Luke Falk on injured reserve.
The Associated Press contributed to this report.