In Tuesday's statement, the 23-time Grand Slam victor insisted she would still be competing in the French Open later in May.
Wozniacki, 28, withdrew from her first-round match against American Danielle Collins because of a leg injury, having lost the first set 7-6 (7-5).
Serena Williams was forced to withdraw from the Internazionali BNL d'Italia ahead of her second-round clash with sister Venus Williams citing a continuing left knee injury, the tournament announced today.
"I look forward to seeing you all at the French Open and next year in Rome", she added.
The French Open gets underway on May 26.
Tournament organizers made the announcement a day after Serena opened her clay-court season with a straight-sets win over Swedish qualifier Rebecca Peterson.
As a result of this latest withdrawal, Venus advances into the third round via a walkover.
American Collins, 25, will now play two-time Grand Slam victor Garbine Muguruza of Spain in the second round of the Italian Open on Wednesday following Wozniacki's withdrawal.
Serena had also played Petersen in the second round at the Miami Open in March before withdrawing with a knee injury. She has done so in her last three tournaments.