Rondon would get a $2.5 million salary next season and would include a team option for 2021 with a $500,000 buyout.
The 31-year-old right-hander is a seven-year veteran who helped the Chicago Cubs win the World Series in 2016. He pitched last season for the Houston Astros and had a 3.71 ERA over 62 appearances, including one start.
Rondon has 92 saves and could be a candidate to close games for the D-backs, though Archie Bradley returns after handling the closer role for much of the second half of last season.
The Arizona Republic first reported Rondon’s signing.
The Associated Press contributed to this report.