Local organizers say the program will feature four singles matches and one doubles match at the Mediolanum Forum.
Both Williams sisters recently returned from lengthy injury layoffs, and Serena won the Rogers Cup in Toronto on Sunday.
Schiavone won last year's French Open and was runner-up this year, while Pennetta became the first Italian woman to enter the top 10 of the rankings in 2009.
The Williams sisters did not play when Schiavone and Pennetta led Italy past the United States for the 2009 and 2010 Fed Cup titles.
In other developments Monday, Serena
soared from No. 80 to No. 31 in the WTA rankings following
her victory in the Rogers Cup.
Williams has won her last two tournaments, the other title
coming at the Stanford Classic two weeks ago. She has played in
four tournaments since her return.
She beat Samantha Stosur 6-4, 6-2 on Sunday in Toronto, the
latest step in a comeback from injury and illness that sidelined
her 49 weeks. The U.S. Open starts Aug. 29.
Information from The Associated Press was used in this report.