A source confirmed that the former league MVP and Toronto had agreed on a contract. Attempts to reach a club spokesman were not immediately successful Monday afternoon but a news conference is expected later this week.
Toronto selected the 35-year-old De Rosario in Stage 2 of the MLS re-entry draft last month after D.C. United opted not to pick up his option at the end of the season.
Had De Rosario not agreed to Toronto's contract offer, TFC would have held the right of first refusal for him in MLS.
De Rosario made US$654,300 in 2013 but will undoubtedly earn less in Toronto, which will be looking for the Canadian international to mentor younger players while offering support to a new-look marquee attack.
Toronto has already signed Brazil's Gilberto with England star Jermain Defoe expected to join him soon as part of a megabucks designated player strike force.
A native of Toronto, De Rosario currently ranks sixth on the all-time MLS scoring list with 103 goals. Twenty-seven of those came in a Toronto FC jersey from 2009 to 2011.
He was traded to New York just two games into the 2011 season after a public contract dispute. De Rosario upped the money ante in September 2010 when he celebrated a goal in a 3-2 home loss to San Jose by pretending to sign a cheque.
Much has changed since then in Toronto. Only two players (Ashtone Morgan and Doneil Henry) remain from the matchday 18 of De Rosario's last game in a Toronto shirt — a 2-0 win over Portland on March 26, 2011.
DeRo is the latest piece of the Toronto FC puzzle as manager Ryan Nelsen continues his rebuild.
Since the end of the 2013 season, Toronto has also acquired MLS experience in the form of Brazilian midfielder Jackson and defender Justin Morrow while picking up draft picks in trading away the rights of goalkeeper Stefan Frei and midfielder Bobby Convey.
Toronto first acquired De Rosario in 2009 from Houston in exchange for defender Julius James and allocation money. De Rosario, who had scored 15 of Toronto's 33 goals in 2010, was subsequently shipped out in exchange for midfielder Tony Tchani, defender-midfielder Danleigh Borman and a first-round pick.
Toronto's MLS record since De Rosario was traded away is 16-50-34.
De Rosario, a 13-year MLS veteran, has played 324 regular-season and 24 playoff games in MLS. He started his career with San Jose and Houston, winning four league titles.
A finalist for MVP in 2005 and 2006, he has been chosen to the league's Best XI six times. De Rosario has also captured MLS Goal of the Year honours twice, in 2004 and 2005.
He hoisted the MLS Cup in 2001 and 2003 with San Jose and 2006 and 2007 with Houston, earning MLS Cup MVP honours in 2001 and 2007.
DeRo finished 2011 with D.C. United, winning the Golden Boot as the league's top scorer and MVP honours.