Schneider, a 38-year-old unrestricted free agent, had 11 goals and 41 assists in 68 games with Detroit last season, his fourth with the Red Wings.
Ducks general manager Brian Burke said in statement Sunday that Niedermayer "has informed me that he is leaning toward retirement."
"Typical of his character and leadership, he made the call this morning in order to allow us to make alternative plans in the event he does not return," Burke said.
"Although he has not retired and would be welcomed back, we felt adding another top NHL defenseman was critical to defending our championship. Mathieu Schneider fits into that category and will be a great addition to our team."