Ferrero, champion at Roland Garros in 2003, has played only two tournaments this year.
Roddick, the U.S. Open champ the same year, pulled out of the Italian Open doubles final last weekend and this week's Open de Nice to give himself a chance of recovering in time for Roland Garros, which starts on Sunday.
Roddick, ranked 11th, has lost his last four singles since mid-March.
Organizers also said on Thursday that Richard Berankis of Lithuania pulled out. They will all be replaced by lucky losers.
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