The 22-year old right-back leaves New York Red Bulls after two seasons with the club and although they rate him highly, the Red Bulls believe he needs regular first team football, hence the decision to trade him.
"We want to thank Jeremy for his service to the club," Red Bulls general manager Erik Soler said in a statement. "We think that this is a mutually beneficial decision for Jeremy and the club.
"At his age and given his bright future, Jeremy needs to play more matches and we believe that this is the best move for him."
Timbers technical director Gavin Wilkinson was delighted to welcome a talented player to the club.
"Jeremy is a versatile, young footballer who has a tremendous upside," he said in a statement.