The contract breaks down as a $1 million salary, a $250,000 buyout and a $2.5 million mutual option for 2020. MLB Network was first to report the deal.
The 35-year-old Sipp bounced back nicely after a subpar year in 2017 to post a career-low 1.86 ERA in 54 appearances last season. He was 3-1 with a career-best 1.03 WHIP and 42 strikeouts in 38⅔ innings for the NL West champion Astros.
He pitched in at least 40 games in each of his five seasons with Houston, which signed him early in the 2014 season as a lefty specialist for the bullpen after he was released by San Diego.
Drafted by Cleveland in 2004, he made it to the major leagues in 2009. Sipp was traded to Arizona in 2012, then became a free agent after the 2013 season. He signed with San Diego, got released and joined the Astros in May 2014.
Houston gave him a deal paying $6 million in each of the next three seasons. He joined a team coming off its third straight 100-plus-loss season and was a key part of a bullpen that helped the 2015 Astros reach the postseason for the first time since 2005. He had a then-career-low 1.99 ERA that season and appeared in all six of Houston's postseason games and allowed one hit in 5⅓ scoreless innings.
Sipp was left off the postseason roster when the Astros won the 2017 World Series because of his ineffective pitching during the regular season.