The person spoke on condition of anonymity because Baez must pass a physical for the contract to be complete.
Baez strengthens the back end of Philadelphia's bullpen. The 32-year-old right-hander has 114 career saves. He was 4-6 with a 4.02 ERA in 59 games with Baltimore last year.
Baez could be used as a setup man along with Ryan Madson and J.C. Romero, and he's a potential option as a closer if Brad Lidge struggles again this year.
The Baez deal likely means that Chan Ho Park won’t be back in Philly, said MLB.com.