O'Byrne has a goal and three assists in 34 games this season for Colorado, which currently owns the worst mark in the NHL.
The 28-year-old O'Byrne joins a Maple Leafs squad that's in the thick of the Eastern Conference playoff chase. He could help add more defensive stability to a team that's surrendering an average of 2.67 goals a game.
Colorado originally acquired O'Byrne from Montreal on Nov. 11, 2010. He was taken by the Canadiens in the third round of the 2003 draft.