When the Philadelphia Union began the off-season with a trio of signings of CONCACAF players, the team looked well on its way to building a juggernaut. The additions of Costa Ricans Josue Martinez and Porfirio Lopez and Panamanian Gabriel Gomez looked like the final major moves of a team poised to challenge for an MLS Cup.

Little could anyone have known that, within a span of two days, the Union would see both star forward Sebastien LeToux and standout goalkeeper Faryd Mondragon leave the club.

On Tuesda, the Union dealt Sebastien LeToux to the Vancouver Whitecaps for allocation money in the biggest and most surprising move of the MLS off-season. On the surface, the trade looks to be a shocking one, but it was a strategic move by the Union to get value for LeToux before his contract expired at the end of the upcoming season.

The move is a risky one for the Union, who now go into the 2012 season without a proven MLS goal scorer, but when it became clear that LeToux would not re-sign with Philadelphia for anything short of a big-money Designated Player contract, Philadelphia was forced to decide whether it was worth it to keep him for one more year or if the team was better off turning to its younger forwards and getting something for LeToux.

That was the motivation behind Philadelphia turning down trade offers for Mwanga and sending LeToux on a trial with Bolton. The Union's dream scenario was to have LeToux be sold to Bolton, where Philadelphia could have used the relatively modest transfer revenue to spend on its youth academy while also avoiding the sight of LeToux in MLS.

That plan dissolved when LeToux returned early from his Bolton trial, but the Union didn't have to look far for a team with allocation money and interest in LeToux. Vancouver head coach Martin Rennie already had a stocked stable of forwards but wasn't about to pass on a proven commodity like LeToux.

While the acquisition of LeToux is a bonus for the Whitecaps, Vancouver was already overloaded at forward. Now the team boasts LeToux, Eric Hassli, Camilo Sanvezzo, Darren Mattocks, Omar Salgado, Long Tan, Atiba Harris and Etienne Barbara. While some of those eight forwards can play as wingers, that is still too big a stockpile for Vancouver to possibly hold on to.

A potential forward trio of Hassli, Sanvezzo and LeToux could be the best in MLS, but it also raises questions about the future of teenage forward Omar Salgado and rookie first-round pick Darren Mattocks. The No. 1 overall pick in the 2011 MLS Draft, Salgado has drawn considerable interest from European clubs who are in love with the potential he has shown with various US youth national teams. As for Mattocks, he had plenty of fans leading up to the draft among MLS teams who were enamored with his blazing speed. He could certainly fetch a good price if the Whitecaps put him on the market.

As for the Union, with LeToux gone, a heavy burden will fall on Mwanga to not only replace LeToux but also justify his own high salary. Mwanga has two years remaining on his current MLS contract, and sources tell FOX Soccer that the salary in the fifth year of his deal will be upwards of $500,000. This makes 2012 vital for Mwanga. A strong year could either lead to a new contract with the Union or some transfer offers from abroad.

Mwanga will be hard-pressed to duplicate LeToux's production (25 goals, 20 assists in two seasons with Philadelphia), but he won't try to fill the void alone. Young forward Jack McInerney has excelled with the US Under-23 national team and could be ready for a bigger role.,Colombian veteran Lionard Pajoy is expected to compete for a starting role, Costa Rican newcomer Josue Martinez is a promising speedster, and rookie first-round pick Chandler Hoffman is a quality finisher with serious potential.

That collection of forwards isn't likely to ease concerns among Union fans who are understandably upset at losing the team's most beloved player. In fact, Philadelphia head coach Peter Nowak is likely to face some backlash for his decision to unload LeToux; at least, until the team gets on the field and starts producing results.

It isn't helping Nowak that Colombian veteran goalkeeper Faryd Mondragon asked to leave the Union to rejoin childhood club Deportivo Cali in a shock move that left the club scrambling. The Union had little choice but to grant Mondragon, 40, his wish or fear burning bridges in Colombia.

The Mondragon loss could be an easier one to deal with if young goalkeeper Zac MacMath can build on the promise he showed in limited appearances as a rookie in 2011. That doesn't change the fact that the Union have lost their two most productive and popular players in a two-day span. It is a public relations nightmare - one Nowak had to know he would face as soon as he made the decision to offload LeToux.

The Union will need to get off to a fast start to help ease the fears of worried Union fans, and Nowak will be relying on a very young team to make that happen. If Mwanga and MacMath can step up produce, then the Union will move on and continue building on 2011's playoff qualification. If the two youngsters don't deliver, then Nowak will start feeling the heat well before summer arrives.