The Philadelphia Union have a glaring need at centerback and have taken a major step toward filling it, pulling off a trade that will help them land a central defender who has enjoyed success in Major League Soccer before.

The Union have signed former Chicago Fire defender Bakary Soumare. In order to pave the way for signing Soumare, Philadelphia completed a trade with the Vancouver Whitecaps to move into the top spot in the MLS Allocation order in order to select Soumare. Under MLS guidelines, a player who left MLS via transfer must go through the MLS Allocation order unless the team that sold him did not spend the money received in the original transfer.

A 2008 MLS Defender of the Year finalist, Soumare excelled in central defense for the Chicago Fire in 2008 and 2009 after originally being drafted in 2007 out of the University of Virginia as a defensive midfielder. He left the Fire in the summer of 2009 when he was sold to newly-promoted French First Division side Boulogne for an approximate $2.1 million transfer fee. That was a record fee for an MLS defender at the time, a record that stood until Tim Ream's transfer to Bolton in January (a transfer believed to be around $3 million).

The 6-foot-4 native of Mali became a regular for Boulogne, but the club was quickly relegated to the second division. Major knee surgery sidelined Soumare for a year and upon his return to health he went on loan to German second-division side Karlsruhe. With Boulogne set for relegation to the French third division, the club has left Soumare walk away from the remaining time in his contract to return to MLS.

Soumare, 26, will be eligible to play for the Union once the summer transfer window opens on June 27th. He has been out of action for several months though, and will likely need to work his way back to full fitness before he can take his expected place in the Union starting lineup. A spot that has been filled admirably in recent weeks by converted midfielder Amobi Okugo. Soumare brings size, athleticism and top-notch on-the-ball skills to the Union defense.

The Union have been courting Soumare for more than three months, with his acquisition part of the long-term plan of former Philadelphia head coach Peter Nowak, who traded away veteran defender Dan Califf in anticipation of the arrival of Soumare. Nowak parted ways with the Union last week, and has been replaced by interim head coach and long-time assistant John Hackworth.

Philadelphia's selection of Soumare in the MLS Allocation Order means the New England Revolution have moved into the top spot of the order, which is used by MLS to allocate players returning to MLS from abroad, be they current and former US national team players or former MLS standouts returning from abroad.

Vancouver's willingness to part with the top allocation spot should put to rest rumors that the club was lining up a move for US national team centerback Carlos Bocanegra. The Rangers defender could be on the move from the unstable Scottish powerhouse, but it appears a little less likely he will make his way back to MLS, at least not to the Whitecaps, which had initial interest in Bocanegra but have found a strong centerback tandem in Jay DeMerit and Martin Bonjour.