It happens in every Grand Slam. Someone makes it to the quarterfinals that you wouldn’t expect. Last year at Wimbledon, the surprise semifinalist was Marat Safin. People predicted it would lead to a resurgence in his career, which it didn’t.

Let’s take a quick look at the past three Wimbledons and see which players made it to the quarterfinals that were unexpected.
In 2008, Feliciano Lopez, Marat Safin, Mario Ancic, Rainer Scheuttler, and Arnaud Clement were the unlikely quarterfinalists. Unusual facts came up. For example, Scheuttler and Clement played each other in the quarterfinals. Both had reached the finals of the Australian Open once. Both had lost to Andre Agassi. Mario Ancic had been the last player to beat Federer at Wimbledon.
In 2007, Juan Carlos Ferrero, Richard Gasquet, Marcos Baghdatis, and Tomáš Berdych made it to the quarterfinals. That Wimbledon fell closer to form. These four were seeded 20, 12, 10 and 7 respectively. Indeed, Gasquet generally plays pretty well at Wimbledon, but won’t be there this year due to his issues with cocaine charges.
In 2006, Mario Ancic, Radek Stepanek, Jonas Bjorkman, Lleyton Hewitt, Marcos Baghdatis, and Jarkko Nieminen made the quarter finals. As you can see, Ancic played Federer in 2006 and 2008. Baghdatis did well in 2007 as well. Bjorkman was a surprise semifinalist, being unseeded in 2006.
It’s pretty hard to predict the players that are likely to make it far outside the top 4 players in the world. People predict Jo-Wilfried Tsonga because he made it to the 4th round of Wimbledon one year, made it to the finals of the Australian, and is generally a pretty talented guy. For similar reasons, some have picked Monfils to do well.
Then, there are players that have gotten good, but have yet to have a breakout performance at Wimbledon. This would include Fernando Verdasco and Juan Martin del Potro.
Then, there are the players that did well at the French. In particular, Robin Soderling is given a nod at doing well at Wimbledon. His big serve, flat style strokes, recent mental toughness make him an attractive outside shot at making it through a few rounds. Similarly, Tommy Haas not only gave Federer all he could handle, but won Halle this past week beating Novak Djokovic.
Can the Americans finally do well? James Blake and Mardy Fish have big games that should translate to grass. Can they play well enough consistently? Blake made the finals of Queen’s. And there’s Andy Roddick, still in the top ten. Made the finals twice, but hasn’t had a good Wimbledon in a while.
You can be sure there will be a few surprises this year too.