Arthur Joseph "Tillie" Shafer (March 22, 1889 – January 10, 1962) was a Major League Baseball infielder with the New York Giants from 1909 to 1913.

While attending Santa Clara University, Shafer was one of the most accomplished college athletes on the west coast, winning numerous track and field medals, in addition for playing baseball for the then-Missionites of Santa Clara.

A young, shy man from a wealthy family, Shafer was hassled from the moment he first entered the Giants' clubhouse as a rookie.

[1] After two seasons of sitting on the bench, Shafer took 1911 off, having arrived back home after sailing to Japan to instruct a university baseball team.

In the after-events of the decisive Game 8, teammates ragged on Fred Snodgrass for a dropped fly ball that had Shafer leap to his defense for heated confrontations.