Washington fire sale and got rid of people who could acquire draft capitol for.
SF tried to resign him but didn't have any cap space. He also had a neck injury that hampered his play and SF didn't want to pull cap gimmicks unsure if he'd be 100% after neck surgery. Despite that injury and pending surgery, he was also a hot free agent last year.
Saints weren't sure if he'd comeback 100% either after surgery, so they signed him to 1 year deal with the money he wanted.
He was also garnering lots of interest this free agency.