O’Leary, 26, was selected in the sixth round by the Bills in the 2015 NFL draft. However, he was waived at the start of the season and later added to their practice squad. He was eventually promoted to their active roster during his rookie year and just finished his rookie contract.
He re-signed with Buffalo this offseason to a one-year exclusive rights deal but was among their final roster cuts coming out of the preseason.
In 2017, O’Leary appeared in 15 games and recorded 22 receptions for 322 yards (14.6 YPC) and two touchdowns.