The Boston Globe reported that the deal is worth $8.2 million and includes a $6 million bonus.
A native of Habana, Cuba, whose defensive skills have drawn comparisons to Ozzie Smith, Iglesias has been added to the club's 40-man roster and will play for the Mesa Solar Sox in the Arizona Fall League, which starts next month.
In 75 games with Los Vaqueros de La Habana -- a member of Cuba's Serie Nacional -- during the 2007-08 season, the 5-foot-11, 175-pound Iglesias batted .322 (101-for-314) with 11 doubles, 39 RBIs and 51 runs scored.
Iglesias established residency in the Dominican Republic before signing with Boston.
John Barone is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.