Seattle announced the signings Thursday.
Lowe's signing is the most notable. He appeared in 162 games with Seattle between 2006-2010.
Lowe was part of the trade that sent Cliff Lee to Texas during the 2010 season. He spent last season in the Cleveland organization, splitting his time between the Indians and Triple-A Columbus.
Germano, a nine-year veteran, spent most of last season in the Texas organization pitching at Triple-A Round Rock.
Rivero was claimed off waivers by Seattle on Nov. 3, but was non-tendered a month later. Rivero made his major league debut last season with Boston and currently leads the Venezuelan Winter League in home runs with 14.