The team announced the deal on Thursday. Rondon gets a $2.5 million salary next season and the deal includes a team option for 2021 with a $500,000 buyout. He could potentially get a base salary of $4 million in 2021 which could escalate to $5 million depending on how many games he finished on the mound.
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 Houston and had a 3.71 ERA over 62 appearances, including one start, as the Astros advanced to the World Series before losing to Washington.
The Diamondbacks finished with an 85-77 record last year and Rondon said he's excited to join a team that he believes is on the rise.
"Last year, they were really close to going to the playoffs,'' Rondon said. "And I think as a player, that challenge for me is huge. I like the way they play and the way they think and it was an easy decision for me to go to the D-backs.''
Rondon has experience as a closer and could be used in that role in Arizona, but the team has other options including Archie Bradley, who finished with 18 saves last season and was especially effective in the second half of the year. Hazen said Bradley "performed very well for us'' even though next year's bullpen roles weren't completely decided.
"I would not say anything is set," Arizona GM Mike Hazen said. "I would hope that everyone comes in ready to compete. I think there's probably still some opportunity for competition and we have a lot of good young pitchers pushing up who are looking for opportunity to take roles.''