Wimbledon, which has just gotten underway today, is a seeded tournament, like all major tennis events and other elimination tournaments.  Competitors are ranked according to strength and placed into the elimination bracket in a way that matches the strongest against the weakest.  For example, seeding is designed so that when the quarter-finals are reached, the top seed (the strongest player)  will face the 8th seed, the 2nd seed will face the 7th seed, etc.   From the blog Straight Sets:

When Rafael Nadal withdrew from Wimbledon on Friday, there was a reshuffling of the seeds that may have raised a few eyebrows. Here is how it was explained on Wimbledon.org:

The hole at the top of the men’s draw left by Nadal will be filled by the fifth seed, Juan Martin del Potro. Del Potro’s place will be taken by the 17th seed James Blake of the USA. The next to be seeded, Nicolas Kiefer moves to line 56 to take Blake’s position as the 33rd seed. Thiago Alves takes Kiefer’s position on line 61 and is a lucky loser.

Was this simply Wimbledon tweaking the draw at their whim or was there some method to the madness?

Presumably tournaments are seeded in order to make them as exciting as possible for the spectators.  One plausible goal is to maximize the chances that the top two players meet in the final, since viewership peaks considerably for the final.  But the standard seeding is not obviously the optimal one for this objective:  it makes it easy for the top seed to make the final but hard for the second seed.  Switching the positions of the top ranked and second ranked players might increase the chances of having a 1-2 final.

You would also expect that early round matches would be more competitive.  Competitiveness in contests, like tennis matches, is determined by the relative strength of the opponents.  Switching the position of 1 and 2 would even out the matches played by the top player at the expense of unbalancing the matches played by the second player, the average balance across matches would be unchanged.  If effort is concave in the relative strength of the opponents then the total effect would be to increase competitiveness.

When you start thinking about the game theory of tournaments, your first thought is what has Benny Moldovanu said on the subject.  And sure enough, google turns up this paper by Groh, Moldovanu, Sela, and Sunde which seems to have all the answers.  Incidentally, Benny will be visiting Northwestern next fall and I expect that he will be bringing his tennis racket…