The oldest current player is Chris Chelios. I am guessing at the all-time oldest player to be Gordie Howe.
Jamie Moyer on the Philadelphia Phillies. He is 47 years old.
Jamie Moyer, a Phillies pitcher, at age 48
Jamie Moyer of the Philadelphia Phillies, age 45.
Gordie Howe is the oldest player ever to play in Detroit, but today it is Nick Lidstrom