The 36-year-old De Rosario, a former league MVP, is the all-time leading scorer for both Toronto FC and Canada.
Other Toronto FC players available are defender Ryan Richter, midfielder Jeremy Hall and striker Andrew Wiedeman. Also in the draft are Vancouver Whitecaps defender Carlyle Mitchell and midfielder Mauro Rosales, as well as Montreal goalie Troy Perkins and defenders Matteo Ferrari and Futty Danso.
Players chosen in Stage 1 of the MLS re-entry process have to have their contract option exercised or get a "bona-fide" offer.
The re-entry process covers players at least 23 years old with a minimum of three years of MLS experience whose options were not exercised. It also includes players out of contract who have not received "a bona-fide offer" and who are at least 25 years of age with a minimum of four years of MLS experience, and/or players at least 30 years old with a minimum of eight years of MLS experience.
Stage 2 goes next Thursday with clubs then able to renegotiate contracts with the players.
Other former Toronto FC players included in the draft are Edson Buddle, Bobby Convey, Aaron Maund, Nathan Sturgis and Marvell Wynne.
Canadian international Nana Attakora, whose contract option was declined by D.C. United, is also available.