The deal was announced Monday.
The 38-year-old Contreras was a key member in the bullpen for the four-time NL East champion Phillies in his first season as a full-time reliever.
He was 6-4 with four saves and a 3.34 ERA in 67 games in his first season with the Phillies. Contreras went 1-0 and threw four scoreless innings in the postseason.
Contreras is 77-67 with a 4.55 ERA in 258 career games, including 175 starts, with four teams.