Bill Johnston, director of public relations for the team, announced the deal via Twitter.
Meachem was selected by the New Orleans Saints in the first round of the 2007 NFL Draft (27th overall). He started just 25 games in four seasons in New Orleans, with 141 catches for 2,269 receiving yards and 23 touchdowns.
Earlier Tuesday, the Tampa Bay Buccaneers announced they had signed former Chargers receiver Vincent Jackson to a five-year deal. San Diego declined to apply the franchise tag to Jackson for a second consecutive year.
â¢ San Diego released left tackle Marcus McNeill due to a history of neck injuries and to clear cap space, though there's still a chance he could be re-signed. McNeill, who missed the final seven games of 2011 with a neck injury, had to pass a physical by Thursday to qualify for his $10 million salary.
The Associated Press contributed to this report.