Trivia time #3: Who are these 25 starting pitchers?

These are the only 25 starting pitchers since 1919 to do what?

Player ▴
Andy Messersmith
Art Nehf
Frank Viola
Fred Norman
Fred Sanford
George Turbeville
George Uhle
Hal Newhouser
Jack Sanford
Johnny Marcum
Johnny Podres
Larry Dierker
Les Sweetland
Manny Salvo
Matt Young
Mickey McDermott
Nate Andrews
Orval Grove
Robin Roberts
Roger Clemens
Sad Sam Jones
Sal Maglie
Steve Hargan
Wade Miller
Warren Spahn

Provided by Baseball-Reference.com: View Play Index Tool Used
Generated 11/23/2011.

This, I think, is a very tough question.