Lots of times.
The first 5 World Series MVPs were pitcher, Johnny Podres, Don Larsen, Lew Burdette, Bob Turley, Larry Sherry. Also Whitey Ford, Ralph Terry, Sandy Koufax (twice), Bob Gibson (twice), Mickey Lolich, Rollie Fingers, Bret Saberhagen, Frank Viola, Orel Hershisher, Dave Stewart, Jose Rijo, Jack Morris, Tom Glavine, John Wetteland, Livan Hernandez, Mariano Rivera, Curt Schilling and Randy Johnson (tied in 2001), Josh Beckett, and Cole Hamels.
In 1968 both regular season MVPs were pitchers, Bob Gibson and Denny McLain. Others include Roger Clemens, Willie Hernandez, Mike Marshall, Vida Blue, Rollie Fingers, Hal Newhauser (2 in a row), Bobby Shantz, Sandy Koufax, Dizzy Dean, Carl Hubbell, etc.