Rivero, 25, was a reliever for Industriales in Cuba's Serie Nacional and was a teammate of left-hander Gerado Concepcion, whom the Cubs signed last year. In his last season in Cuba in 2010-11, Rivero compiled a 3.06 ERA with 38 strikeouts and 21 walks over 47 innings. The right-hander pitched briefly at the FISU World University Championships in Japan in 2010.
His bonus money will be exempt from the Cubs' 2012-13 international bonus pool. Cuban signings are exempt if the player is at least 23 years old and has played in Serie Nacional for at least three seasons.
Last season, Concepcion, 20, pitched from April 25-June 28 for Class A Peoria, compiling a 2-6 record and 7.39 ERA in 12 starts.
The Cubs' most prominent signing out of Cuba so far has been outfielder Jorge Soler, who agreed last June to a nine-year, $30 million contract. Soler, 20, participating in his first big league camp, was batting .250 (8-for-32) with one home run and three RBIs in 16 Cactus League games before he was assigned to Class A Daytona on Monday.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.