Per Major League Soccer and club policy, terms were not disclosed.
Cooper, 29, has made 188 career appearances since joining MLS in 2006, scoring 72 goals with 16 assists. The seven-year MLS veteran ranks seventh amongst active players with 72 goals, and ranks sixth in MLS with 32 goals over the past three seasons.
"Kenny is a proven goal scorer who is extremely active in the box," said Head Coach Sigi Schmid. "At 6'3, he is a big forward who creates matchup problems for opposing defenders."
Cooper began his professional career with Manchester United where he was loaned to Oldham Athletic of England's League One, scoring three goals in five league games. Cooper has four goals in 10 caps with the U.S. National Team, making his last appearance in 2009.
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