A publicist for Duvall said the 71-year-old actor, an experienced horseman, is doing fine and is expected to make a full recovery before filming starts June 3 in Calgary, Canada.
Duvall will co-star in "Open Range" with Kevin Costner, who described the movie as a story about "a way of life coming to an end and the violence that accompanied it."
Duvall is due in U.S. theaters on May 3 in "A Shot at Glory," as the manager of a second-tier Scottish football team who is forced by the team's American owner (Michael Keaton) to bring on a superstar to improve the team -- so the team can stay in the town where fans have loyally supported it for a century.
"A Shot at Glory" was directed by Michael Corrente ("Outside Providence," "American Buffalo") from a screenplay by Denis O'Neill ("The River Wild").
Duvall -- who won the best actor Oscar for "Tender Mercies" (1983) -- is also due on screens later this year in "Gods and Generals," a prequel to the 1993 Civil War epic "Gettysburg."
He recently finished work on "Assassination Tango," which he wrote and directed. He plays a veteran hit man sent to Argentina to kill a general, who winds up killing time with a beautiful dancer when his target delays his return to the country.