Castillo retired from professional baseball on Sunday, Jesse Dougherty of The Washington Post reports.
Castillo last saw game action with Triple-A Rochester in mid-June, and he's opted to hang up his cleats. The 34-year-old played 10 years in the big leagues and had a .254/.313/.426 slash line with 98 homers in 726 games between the Cubs, Diamondbacks, White Sox, Mariners and Orioles.