Empire of Soccer was the first outlet to report on the rumored interest in the former USMNT player by the New England side.
Llamosa was a part of the Cosmos since their first season of play in 2013, joining after playing the same role at Chivas USA from 2010 to 2012.
He returns to New England after playing for the team in 2002-03.
“Carlos was an excellent player and an even better teammate, and we are thrilled to add his passion and energy to our team,” said Revolution Head Coach Jay Heaps of the signing.
The Revolution finished the 2016 season in seventh place, tied with the Philadelphia Union on points, but missed out on the playoffs by goal differential.
They also faced off against the New York Cosmos in the US Open Cup’s Round of 16 on June 29th, coming back to beat New York 3-2.