The signings give the Crew 29 players heading into the MLS season, which begins on the road Saturday at Chivas USA.
Warzycha, the son of Crew head coach Robert Warzycha, spent the last two seasons with Sporting Kansas City. Before that, he played four years for his hometown college team, Ohio State.
Selected 66th overall in the 2013 MLS supplemental draft in January, Sloan played four seasons at High Point University.
A native of Bay Village, Ohio, Hyland signed his first pro contract after four successful years at IUPUI.