Former teenage soccer phenomenon Freddy Adu has reached another crossroads after an embarrassing snub that has cast doubts over his future with the Philadelphia Union – and beyond.

Adu hoped to revitalize his career by returning to Major League Soccer last year after a difficult stint in Europe but has suffered the ignominy of being dropped from the Union's starting lineup. In last weekend's match against Real Salt Lake, Adu saw just eight minutes of playing time.

The 23-year-old did not start in Wednesday night's MLS regular-season clash at home against the Columbus Crew and played just 13 minutes. Now, as the Union moves towards to the end of a mixed season that will almost certainly see it miss out on the playoffs, the viability of Adu and his $519,000 earnings are being heavily questioned within the league.

"He is kind of like a luxury car," said ESPN analyst and former United States national team star Alexi Lalas. "He is just not practical."

That claim prompted an angry Twitter response from Adu, yet it is a theory that refuses to go away. While Adu's technical ability and talent are beyond question, his versatility, defensive skills and teamwork have all attracted criticism.

The Union's interim head coach John Hackworth has made little secret of his dissatisfaction with Adu, both by limiting his playing time and with a series of public comments. Hackworth berated Adu in the media for an approach he believes is too "self-centered" on the field, an accusation that has plagued the midfielder for years.

Adu, who's scored just three goals in 18 games this season, still has his defenders and spent much of Tuesday re-tweeting positive statements of support about him. That will do nothing to sway Hackworth, however, and may merely inflame a tricky situation further.

There was a time when Adu could have gone elsewhere – to another club, another league or even another continent. Now, though, his options are running out.

"Where is he going to go now?" a leading European soccer agent said to Yahoo! Sports. "He has been all over and never cut it. Everyone knows he can play, but who is going to set up their entire team around one unproven American? I'm glad I'm not touting him around Europe, because you'd struggle to find takers."

The tough part is that Adu's style dictates that he be the star – the central piece or nothing at all. His creativity is outstanding and offensively he has twinkling toes, but his productivity relies on having a great deal of possession, while his defensive abilities have never been especially strong.

Adu has played in Portugal, France and Greece but never found a happy home in Europe, prompting his return to MLS. That has not exactly gone to plan either, with Adu failing to ignite the Union into genuine contenders. As captain, he also couldn't get the U.S. past the Olympic qualifying round as the American squad missed out on the Games in London.

Now it's clear that Hackworth sees the more rugged Michael Farfan, a 24-year-old from San Diego earning just $57,000 a year, as the key to the Union midfield, while Adu, despite all his skill, begins to slip off the radar.

In some ways, Adu is a victim of his own early success. As a 13-year-old he signed a $1 million endorsement deal with Nike. A year later he sealed an MLS contract with DC United and at the time was considered to be the future of American soccer.

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