Philadelphia Manager Charlie Manual had considered starting Joe Blanton or J.A. Happ but decided on Martinez, a 37-year-old right-hander who last pitched nearly two weeks ago in a game against Houston, a report on the Phillies team Web site said Friday.
Martinez is a three-time winner of the Cy Young Award, which goes each year to the top pitchers in the National and American Leagues.
The Phillies and Colorado Rockies, tied 1-1 in their best-of-five playoff, meet Saturday at Coors Field in Denver. Game time is 9:37 p.m. EDT.
Colorado plans to Jason Hammel (10-8), also a right-hander.
Martinez is 5-1 with an ERA of 3.63 since signing as a free agent with the Phillies in July.
Copyright 2009 by United Press International.