The clubs Tuesday also swapped spots in the MLS allocation ranking, with the Union moving up to No. 1 and United down to No. 6. That will give Philadelphia first dibs on the next U.S. national team player to sign with the league.
The 23-year-old White started 21 league games for United last season.
United also announced that defender Dejan Jakovic has moved to Shimizu S-Pulse of Japan’s J-League on a permanent transfer.