Every year, hundreds of rookies touch down in the major leagues for the first time. Each has the same goal: to demonstrate to his team and the fans that he has what it takes to be a baseball star.
Luckily for them, they have a generous margin of error should they not immediately succeed. The fans might not be patient, but most people who matter understand that it takes time to transition to the big show.
Unfortunately, not everyone has this safety net. For many players—failed prospects, faded stars, and wrinkling journeymen—a bad season could signal the end of their careers or at least leave them to struggle for the playing time they once took for granted.
Here's a look at 10 players who could fall off a cliff if they take another step back in 2010.