Evan Longoria’s game-winning home run cleared the left field wall just minutes after the Boston Red Sox had lost to the Baltimore Orioles. With that, the historic collapse was complete. 

The Red Sox held a nine-game lead in the American League Wild Card race at the beginning of September. But, a 7-20 record in the season’s last month meant that it was the Tampa Bay Rays who were celebrating the final berth to the 2011 playoffs.

A lot has changed for the Red Sox since that dreadful night.

Terry Francona resigned as the team’s manager and switched places with former ESPN analyst Bobby Valentine, who was hired by the team on December 1. Jonathan Papelbon, Marco Scutaro and Jason Varitek, all key contributors last season, are no longer with the team.

Newcomers—especially Andrew Bailey and Cody Ross—will be important to the Red Sox finding success in 2012. But there are returning players who must step-up, too.

Here are the top five players that must improve on their 2010 efforts if the Red Sox want to return to the playoffs. 

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