Adu hasn't been in MLS since leaving Real Salt Lake in 2007 for Portuguese giants Benfica. The 22-year-old's soccer career has been stalled because of indifference from Benfica and a failure to impress while on loan with Monaco, Belenenses and Aris.
The American international rebuilt his reputation when Benfica sent him to Turkish second league side Çaykur Rizespor. While in Turkey, Adu scored four goals in only 11 games and made people start to think about him again as a quality player. His Turkish form led to a call up for the United States Men's National Team under Bob Bradley, and received another one under Jurgen Klinsmann (last night).
Union head coach Piotr Nowak said at his press conference that the team would be announcing at least one player tomorrow. Fabio Grosso, who has been linked to the Union twice, will not be coming to Philadelphia, per Nowak.