The Associated Press reports that Haralson acknowledged that he had been traded before the 49ers began a late practice on Monday, but refused to give further details.
"I want to let them announce it," Haralson said.
The Saints have a need at outside linebacker after the team lost starting outside linebacker Will Smith for the season with a knee injury in its 31-23 victory against the Houston Texans on Sunday.
Haralson did not play last season after tearing his triceps in San Francisco's third preseason game. He became expendable for the 49ers when his replacement, Aldon Smith, finished the season with a franchise-record 19 1/2 sacks.
Haralson was selected by the 49ers in the sixth round of the 2006 draft out of Tennessee.