From Wiki:
Walter Clement Pipp (February 17, 1893 January 11, 1965) was an American first baseman in Major League Baseball, now best remembered as the man who lost his starting role to Lou Gehrig at the beginning of Gehrig's streak of 2,130 consecutive games.
On June 2, 1925, Pipp was removed from the Yankees' starting lineup and replaced with Gehrig. The story has become baseball legend:
In the most popular version, one supported in later accounts by Pipp himself (although he wasn't always consistent on the subject, either), Pipp arrived at Yankee Stadium one day in 1925 with a terrific headache. He asked the Yankee trainer for a couple of aspirin. Manager Miller Huggins noted the scene and said, "Wally, take the day off. We'll try that kid Gehrig at first today and get you back in there tomorrow."
As Gehrig went on to play 2,130 consecutive games, Pipp did not get back in there tomorrow. He is later quoted to have said, "I took the two most expensive aspirin in history."
Other sources suggest Yankee manager Miller Huggins may have actually benched Pipp and other veterans in order to "shake up" the slumping lineup. A month later, Pipp received a skull fracture when he was hit by a practice pitch from Charlie Caldwell, an event that had also been mistakenly linked to his initial benching. Pipp was later traded to the Cincinnati Reds before the 1926 season.
LINK: http://en.wikipedia.org/wiki/Wally_Pipp