The former MLS Cup Champion and three-time All-Star first joined the Union on a free agent contract in 2019. He made six league appearances, played in one U.S. Open Cup match, and was crucial depth for a Philadelphia side that experienced some instability at the center back position in 2019.
"We are pleased to welcome Aurelien back to our roster for the 2020 season,” Union sporting director Ernst Tanner said in a statement. "Aurelien is a proven winner with a strong work ethic that is matched by his heart and passion. We look forward to his continued contributions to our defense and leadership on and off the field.”
Prior to signing with the Union, the 33-year-old Collin spread his career across several MLS clubs, beginning at Sporting Kansas City (2011-14), before moving on to Orlando City (2015-16) and the New York Red Bulls (2016-18). He helped SKC to an MLS Cup in 2013 while winning the MLS Cup MVP award. The year before, he took Best XI honors and helped SKC to the Open Cup title.
He also won the Supporters' Shield with the Red Bulls in 2018.