Nowak was one of the best central midfielders in the MLS when he played and he's the only man to ever win an MLS Cup as both a player and head coach. He played for the Polish national team and then in 1998 joined the MLS and played for the Chicago Fire. With Nowak as captain, the Fire won the Cup that same year along with the U.S. Open Cup title, according to the report.
Nowak took the head coaching job for D.C. United in 2004 and won the MLS Cup title his first season. Right now he works with the U.S. national team as an assistant coach. He'd leave that job to take the head position for the Union, whose first season of play is in 2010.
Philadelphia Union CEO Nick Sakiewicz did not comment on the hire when ESPN contacted him and all they will tell us at the moment is, "we're neither denying or confirming" but they did want to let us know there's a big press conference tomorrow.