The club did not disclose terms of the deal.
Saragosa comes to United from the Azerbaijani club Ravan Baku, where he's scored just one goal in eight appearances this season.
"We are pleased to have concluded a deal to bring Marcelo to DC," said D.C. United General Manager Dave Kasper in a statement. "He is well-acquainted with our League and brings additional depth to a midfield that we feel is already one of the best in the League. We look forward to his contributions to our team."
Saragosa first came to MLS in 2004, when Brazilian club Sao Paulo loaned him to the Los Angeles Galaxy. After a brief return to Brazil, the Galaxy signed Saragosa to a permanent deal in August of 2005. That year, the Galaxy won both the MLS Cup and the U.S. Open Cup. Saragosa was traded to FC Dallas for a fourth-round supplemental draft pick in 2007 and went on to make 54 appearances for the Hoops before being traded to Chivas USA for Atiba Harris in 2009. Saragosa made 22 appearances in his only season at Chivas, becoming a free agent after going unclaimed in the 2010 MLS Re-Entry Draft.
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