Ben Affleck, 28, is about to step into shoes previously filled by Alec Baldwin and Harrison Ford, those of CIA analyst Jack Ryan. The actor, reports the Associated Press, will soon start shooting the starring role in “The Sum of All Fears,” about a terrorist attack on the Super Bowl. It is due to open in 2002 and is the fourth film adaptation of novelist Tom Clancy’s series about the spy hero. (Baldwin originated the role of Ryan in 1990’s “The Hunt for Red October,” with Ford stepping in for 1992’s “Patriot Games” and “Clear and Present Danger” two years later.) Also in the cast with Affleck are Morgan Freeman, Bridget Moynahan and Liev Schreiber.