Haralson must pass a physical in New Orleans for the trade to become official.
While leaving 49ers headquarters Monday afternoon, Haralson said he'd been traded and planned to join his new team Tuesday.
A fifth-round draft pick by San Francisco in 2006, Haralson has played in 86 games with 68 starts. He's been credited with 295 tackles, 21.5 sacks, four fumble recoveries and three forced fumbles.
The Saints, who run a 3-4 defense, have lost both projected starting outside linebackers to knee injuries. Will Smith is out for the year, while Victor Butler will miss most or all of the season.