Three-time Champions League-winning goalkeeper Victor Valdes had his contract terminated by mutual consent by Middlesbrough as they cut costs after relegation from the Premier League.
The 35-year-old former Spanish international, a member of the Barcelona side that won the 2006, 2008 and 2011 Champions Leagues, played 28 times for Middlesbrough last season before a rib injury curtailed his campaign.
"Valdes joins fellow goalkeeper Brad Guzan as a summer departure with the USA international heading to join MLS side Atlanta United," said a Boro statement.
Valdes, capped 20 times by Spain and a member of the 2010 World Cup winning squad and Euro 2012 champions, and Guzan will likely be followed by several more players out the door, including highly rated defender Ben Gibson.
Boro, presently without a full-time manager as Aitor Karanka was replaced with caretaker Steve Agnew, finished second from bottom of the table, 12 points adrift of safety.