The person spoke to The Associated Press on condition of anonymity Saturday because the deal has yet to be announced.
Ottavino underwent Tommy John surgery on his right elbow in May. The team is hoping to have him back sometime around the All-Star break.
The 30-year-old Ottavino went on the disabled list in late April with right triceps inflammation soon after he was promoted to closer. Ottavino didn't surrender a run in 10 1-3 innings last season.
Originally selected by St. Louis in the first round of the 2006 draft, Ottavino was acquired off waivers by Colorado in 2012.
The agreement was first reported by CBS.