The Blue Jays are scheduled to make an announcement at 12:30 p.m. Monday from baseball's winter meetings in Florida.
Halladay, who is a free agent, has endured many injuries in recent seasons.
In 2013, he was hampered by shoulder problems and had a 6.82 earned-run average in 13 starts for the Phillies. Halladay's fastball also averaged only 88 miles per hour.
The 36-year-old right-hander won 203 games with a 3.38 earned-run average between the Blue Jays and Philadelphia Phillies, who acquired him in a trade in December 2009.
More to come