The 29-year-old Chicago-born midfielder joins the Crew from Uruguayan top-flight side Bella Vista.
Viana, who was born in Chicago and holds dual USA-Uruguay citizenship, joins Brazilian defender Glauber as recent signings. The left-footed Viana does not take up an international roster spot and can also pitch in at left back, increasing his value to coach Robert Warzycha's side.
“Agustín is a player that brings versatility and experience to our lineup, and we’re pleased to have finalized his signing,” Crew technical director Brian Bliss said in a team statement. “He’s a box-to-box player that provides a lot of energy, and being able to play on the left side of defense or in central midfield gives us flexibility and depth at multiple positions. We look forward to getting him into training camp.”
Although Viana was most recently with Bella Vista, he is a well-traveled player. In between his four stints with the Uruguayan side he spent time at Bella Vista rival Nacional Montevideo, Brazilian side Atletico Mineiro, Romanian club CFR cluj, Italian second-tier side Gallipoli and Greek club Levadiakos.