Five struggling stars who could flourish with move in January window

A move to the Premier League, La Liga -- or even MLS -- could revitalize Mario Gomez's career. Gabriele Maltinti/Getty Images

It's the midseason dilemma every club dreads: You've spent a lot of money on what you hoped would be a marquee signing -- a solution to your needs that would propel you up the table -- but it just hasn't paid off. For whatever reason, your big-money star just isn't firing and, while you could chalk it up to difficulty adapting to a new country, culture or style of football in his first season, when he continues to struggle in Season 2, it becomes a big problem.