Descalso, now a free agent, batted .264/.349/.424 with eight homers and 38 RBIs in 99 games for the Rockies last season. The 30-year-old utility player and seven-year Major League veteran had been with Colorado since 2015.
The 29-year-old Giavotella played 99 games for the Angels in '16, his second year in Anaheim and sixth in the big leagues. The second baseman hit .260/.287/.376 with six home runs and 31 RBIs.
Descalso and Giavotella, neither of whom played for Italy in the three previous Classics, join Pirates catcher Francisco Cervelli, Royals catcher Drew Butera and Indians Minor League first baseman/outfielder Chris Colabello on the roster.
David Adler is a reporter for MLB.com based in New York. Follow him on Twitter at @_dadler. This story was not subject to the approval of Major League Baseball or its clubs.