Mason will be joined by Ravens general manager Ozzie Newsome and coach John Harbaugh at a news conference announcing his retirement Monday afternoon.
The 38-year-old Mason played 15 years in the NFL, six of them with Baltimore. He is the Ravens' franchise leader in receptions (471) and yards receiving (5,777). He ranks second behind tight end Todd Heap with 29 touchdown catches, and he set a single-season franchise record with 103 receptions in 2007.
He began his career with the Tennessee Titans in 1997, and played for them through 2004.