Fifteen photos taken with a cell-phone camera depict Sizemore alone in front of a bathroom mirror. In some of them, he is fully clothed, and in others, he's wearing little to no clothing.
Sizemore told The Plain Dealer that the pictures were meant for his significant other. Major League Baseball and the Players Association were said to be investigating the matter on his behalf.
"These pictures were stolen illegally from my girlfriend's e-mail," Sizemore told The Plain Dealer on Sunday night. "It's now a legal matter that is under investigation. I can't say anything more."
Indians general manager Mark Shapiro told the newspaper, "I have not seen the pictures, but I will look into it."
The Indians issued a statement that said, "We fully support Grady as he deals with this personal matter. The posted photos were stolen from his girlfriend's email account and a legal investigation is under way."
Sizemore is coming off left elbow and sports hernia surgery in September. In 2009, his sixth season, the 27-year-old hit .248 with 18 homers, 64 RBIs and 13 stolen bases in 106 games.
Alden Gonzalez is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.