The 49ers had been shopping Haralson for a few days. He has 21.5 career sacks but missed last season with a torn triceps.
San Francisco is deep at outside linebacker, like it is at most positions on its roster. Haralson likely would have been cut if not traded, considering the Niners are still well over the 75-man roster limit with less than 24 hours to go before the deadline.
The trade means good things for rookie linebacker Corey Lemonier, who was drafted in the third round out of Auburn. He has performed well enough in the preseason to give the 49ers enough incentive to clear the depth chart for him a bit.
The 49ers likely did not receive much more than a low draft pick as compensation for Haralson.
For the Saints, Haralson should be a nice addition to their 3-4 defense that is in need of pass rushers. Will Smith was injured in their third preseason game and will reportedly miss the entire season, so depth was needed.