In nine big league seasons, split between the Marlins, Tigers, D-backs and Reds, Willis compiled a 72-69 record with a 4.17 ERA.
As a member of the Marlins in 2003, Willis was named the National League Rookie of the Year, but he has not pitched in the Majors since 2011.
Willis, 31, was an All-Star in the Atlantic League this season and posted a 2.56 ERA in his 14 starts with Long Island.
William Boor is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.