Roger Federer seeded above Rafael Nadal at Wimbledon

Roger Federer, right, is congratulated by Rafael Nadal after winning the men's singles final at the Australian Open, on Jan. 29, 2017. (Dita Alangkara / AP)

WIMBLEDON, England -- Eight-time champion Roger Federer was seeded No. 2 for Wimbledon, one spot ahead of Rafael Nadal, reversing their positions in the ATP rankings and creating a debate about whether the All England Club's seeding system should be changed.

Top-ranked Novak Djokovic, the defending champion, was seeded No. 1 on Wednesday at the grass-court Grand Slam tournament, where recent results on the surface are used to help determine seedings. The other majors do not do that.

Nadal told a Spanish TV station that he doesn't think it makes sense that Wimbledon is the only tournament that uses its own seeding system. Former U.S. Davis Cup captain Patrick McEnroe and former player and coach Brad Gilbert tweeted that they thought Nadal should have been seeded No. 2.

The ATP's top 32 men are seeded at Wimbledon, but the order is based on a formula that gives players additional credit for ranking points earned at tournaments played on grass over the preceding two years. That allowed Federer, who won his 10th title at Halle, Germany, last week, to jump ahead of Nadal, who potentially could have to beat both Djokovic and Federer to win what would be his third championship at Wimbledon.

Nadal is coming off his record 12th title at the French Open, which is played on clay, and he did not enter any sort of tuneup event on grass this year. He rarely does.

While Nadal did reach the Wimbledon final in five consecutive appearances in the tournament from 2006-11, he had not been so successful of late until a run to the semifinals last year. From 2012-17, Nadal never made it past the fourth round at the All England Club, including one exit in the first round and a pair in the second.

There were other examples of shifts from rankings to seedings. Last year's runner-up, Kevin Anderson, was seeded No. 4, even though he is ranked only No. 8 this week; 2018 semifinalist John Isner is seeded No. 9, ranked No. 12; 2017 runner-up Marin Cilic is seeded No. 13, ranked No. 18.

This year's women's seedings at the All England Club strictly follow the WTA rankings, so French Open champion Ash Barty is at No. 1.

Naomi Osaka is No. 2, followed by Karolina Pliskova.

Seven-time Wimbledon champion Serena Williams is seeded 11th, the same place she holds in this week's rankings. A year ago, early in her return to the tour after having a baby, Williams was ranked just 183rd but seeded 25th.

She wound up reaching the final before losing to champion Angelique Kerber.

The draw is Friday; play begins Monday.