Hiroyuki Nakajima (?? ??, Nakajima Hiroyuki, born July 31, 1982), nicknamed "Nakaji", is a Japanese professional baseball infielder for the Yomiuri Giants of Nippon Professional Baseball (NPB).
He previously played for the Seibu Lions, Saitama Seibu Lions of Nippon Professional Baseball (NPB) and the Oakland Athletics organization.
Nakajima played in the 2008 Beijing Olympics as well as the 2009 World Baseball Classic for the Japanese national team.
After the 2011 season, his Japanese team, the Seibu Lions, posted Nakajima to Major League Baseball, but Nakajima failed to reach an agreement with the New York Yankees.
On December 17, 2012 he signed a two-year contract with the Oakland A's, champions of the Western Division of the American League.
After spending two years in the A's organization, Nakajima announced in December 2014 that he had reached an agreement with the Orix Buffaloes and would be returning to Japan.