Rafael Nadal, world number 1 and defending Wimbledon champ, has just announced a bombshell. He has withdrawn from Wimbledon. Nadal has had knee tendonitis for several months. Although he did not blame it for his French Open loss to Robin Soderling, he had been out of sorts since Madrid.

Nadal had withdrawn from Queen’s Club where he was defending champion, citing his knee problems.

To prep for Wimbledon and determine if he was match-ready, Nadal played two exhibitions at Hurlingham Club in London. Yesterday, he lost to Lleyton Hewitt, 6-4, 6-3. Today, he lost to Stanislas Wawrinka, 4-6 7-6 (10-3). The two did not play a full third set, but played a champion tiebreak instead. Nadal had been expected to give his decision following that match but postponed the announcement until 7 PM London time.

Since Monday’s schedule has yet to be announced, there’s likely to be some shuffling of the pairings due to Nadal’s withdrawal. This should hopefully clear up in the next day or so.

Murray appears to be the primary benefactor. When the draw was announced this morning, Murray was in Nadal’s half of the draw. Federer also stands to benefit from the withdrawal. The truth, of course, that given the severity of his knee condition, Nadal would probably have exited earlier than the finals so Federer would have been unlikely to meet him.

Gael Monfils withdrew earlier, presumably due to knee problems as well. Tommy Haas benefitted by his withdrawal and was given the 24th seed. Haas had been unseeded, despite his win at Halle this year.

Although Federer was already considered the prohibitive favorite to win Wimbledon especially in light of Nadal’s injury, this news would likely make him even more favored. Much like the French Open, this puts pressure immediately on Federer again, although the British press will focus its spotlight on local favorite, Andy Murray.

Two players that might sneak under the radar are Andy Roddick and Novak Djokovic. Roddick has historically performed well, and Djokovic has performed poorly at the Australian and French Open, by his rather lofty standards. Grass appears to be Djokovic’s weakest surface, as evidenced by a loss to Tommy Haas. Still, he’ll want to show that he’s among the tennis elite.

Wimbledon starts Monday.

ADDENDUM. Wimbledon has updated the draw in light of Nadal’s withdrawal. del Potro, who was in Djokovic’s quarter, takes Nadal’s slot. James Blake takes del Potro’s slot. Nicolas Kiefer, who was unseeded, is now seeded 33rd, takes James Blake’s spot, and Thiago Alves, a lucky loser, takes Kiefer’s spot.

This is bad for del Potro because Nadal’s quarter looked to be the toughest quarter. However, he doesn’t have to meet a top 4 seed until the semifinals. So that’s good. Blake was slated to meet Santoro, who is in the semifinals of a grass court tournament this week. Now Kiefer has to play Santoro.

Federer benefits somewhat because he can’t meet del Potro until the final. However, he may still have to deal with Djokovic. Djokovic has yet to show the great form he had in 2007 or 2008, but he’s beaten Federer this year. He is in Federer’s half.

Also, Marcos Baghdatis, who has historically played well at Wimbledon has withdrawn, also due to a knee injury. He is replaced by Karol Beck.