Colorado Rapids president Padraig Smith hailed the acquisition of Aaronson in a statement.
"Bringing Paxten to Colorado highlights our ambition and belief in his ability to impact our team immediately," he said. "He has proven himself in Europe, gained valuable experience on the international stage with the U.S. Men’s National Team, and brings a dynamic, creative presence to our midfield. He is the exact type of young, hungry player we want to build around at this club, and we are delighted to welcome him to Colorado as we strengthen a team capable of competing at the highest level."