Argerich, who is recovering from surgery, has been advised by her doctors not to travel and has canceled scheduled subscription performances, according to a statement.
Fliter was scheduled to make her debut with the Los Angeles Philharmonic this summer at the Hollywood Bowl.
Fliter, a 32-year-old Argentine, recently won $300,000 as the recipient of the 2006 Gilmore Artist Award. Discussing his reason for choosing Fliter, Daniel R. Gustin, director of the Gilmore Award, spoke of her "astonishing pianist prowess and her overall musicianship."
Fliter will play Argerich's scheduled work, Beethoven's Piano Concerto No. 1 in C major. Charles Dutoit will conduct.