Gulbis took a set off Nadal in Wimbledon 2008
Latvia's Ernests Gulbis has withdrawn from Wimbledon with a hamstring injury, potentially easing 2008 champion Rafael Nadal's passage through the draw.
Gulbis, 21, was the 27th seed and set to face Nadal in the last 32, but his slot is taken by Germany's Philipp Petzschner, who moves to 33rd seed.
Injured Croat Ivo Karlovic and Czech Radek Stepanek had already withdrawn.
And Russia's Dinara Safina and Spain's Maria Martinez Sanchez are out of the women's section and have been replaced.
Former world number one Safina, who was seeded 20th, is suffering from a back injury, while 22nd seed Sanchez has a knee problem.
The two players will be replaced by Melanie Oudin and Kateryna Bondarenko, seeded 33 and 34 respectively.
In the men's section, Stepanek was seeded 22 but is out with knee trouble, which will also sideline him for the Czech Republic's Davis Cup quarter-final against Chile in July.
Big-serving Karlovic was due to have been seeded 25th, but has been troubled by a foot injury.
Victor Hanescu of Romania has been elevated to number 31 seed above France's Julien Benneteau and Petzschner, with Spain's Santiago Ventura entering the main draw as a lucky loser.
At 6ft 10, Karlovic is the tallest player on the tour and reached his first Grand Slam quarter-final at Wimbledon in 2009, losing to Switzerland's Roger Federer.
The 31-year-old Croat was also thought a formidable opponent on grass because of his unique serve, which produced a remarkable 158 aces on his run to the last eight at SW19.
He reached the fourth round of the 2010 Australian Open, losing to Nadal.
And although Gulbis has never reached the third round at Wimbledon, he was also tipped to pose a threat as he was the only man other than Federer to take a set off Nadal in the 2008 tournament, while he lost to Andy Murray in the second round in 2009
Stepanek, 31, reached the final of the Brisbane International in January but has failed to survive beyond the second round of any other tournament this year, losing in the first round of the Australian Open to Karlovic.
The Czech announced in March that he was suffering from fatigue syndrome and withdrew from last week's grass-court tournament in Halle, Germany, because of throat inflammation.
His best finish at Wimbledon came in 2006 when he reached the quarter-finals.