Lawrie, the Scotsman who clawed back a 10-stroke deficit to prevail in a three-way playoff, and Frenchman Van de Velde, who suffered a triple- bogey at the 18th to throw away a seemingly invincible lead, both cited "mental and physical exhaustion" as their reason for withdrawing.
Australia's Stephen Leaney, who held off Darren Clarke, Lee Westwood and Nick Price to become the surprise winner of last year's Dutch Open, will be back to defend his title, while Jose Maria Olazabal is also in the field.
Several players on the fringe of Ryder Cup qualification will be chasing crucial points, with Bernhard Langer (12th in the current standings), Costantino Rocca (29th), Andrew Coltart (11th), Sven Struver (13th) and Alex Cejka (14th) all looking for a good finish.
Speaking yesterday, Olazabal backed Lawrie to handle the pressure of his Ryder Cup debut. "If he copes with the pressure the same way he did in the play-off we don't have anything to fear," Olazabal said. "He proved he is strong enough in the play-off. I don't think he will face any tougher situation than a play-off for the Open Championship."
Laura Davies, who finished sixth in the JAL Big Apple Classic in America last week, bids for back-to-back wins on the European Tour in the German Open, which starts today at Treudelberg, in Hamburg.
The Briton, who won the Chrysler Open in Sweden on her last European outing last month, has an unexpected rival in Catrin Nilsmark, who gained a late wild card entry and will also be out for a second win of the season having landed the Evian Masters in France, beating Davies into second place.
However, Davies already has a win over the Swede at Treudelberg - four years ago she joined the European Tour player Joakim Haeggman in victory over Nilsmark and Sven Struver in an exhibition skins match. "It's the first time I've been back, but I've got good memories and I'm coming into the event very confident," said Davies.
Davies is in her element this week. BMW are one of the sponsors, and they have given her use of a pounds 60,000 limousine. "It's terrific," she said. "I know what I'll be doing in between rounds this week."
Lora Fairclough defends the title she won by three shots last year, but Trish Johnson, winner of the French Open two weeks ago, is a late withdrawal.