The Metros acquired a discovery slot for 33-year-old Juskowiak from the Quakes in exchange for a third-round draft pick in 2005. They used their two allotted discovery slots on Argentines Juan Forchetti and Jose Galvan.
Juskowiak, a member of Poland's silver-medal team at the 1992 Olympics, has played for Lech Poznan, Sporting Lisbon, Olympiakos, Borussia Moenchengladbach, Wolfsburg and Cottbus.
The Chicago Fire has acquired Costa Rican midfielder Jonathan Bolanos. The 25-year-old has played for Deportivo Saprissa and Alajuela in Costa Rica and La Piedad in Mexico.
Columbus dealt Brian Dunseth to Dallas for a conditional draft pick to make room for Northern Ireland international defender Mark Williams, who trained with Columbus last month and has been signed as a discovery player.
Williams, 32, has played 22 games for Watford in the Premier League. Most of his career has been spent in the First and Second Divisions. He played on loan at the end of last season with Stoke City. Williams has 25 caps for Northern Ireland and scored one goal.