I thought this would be interesting to do. Everyone on the active roster is postseason eligible.

My Roster is:

Pitchers (11)
Shawn Chacon
Alan Embree (pitch in blowouts or emergency)
Tom Gordon
Randy Johnson
Al Leiter
Mike Mussina
Mariano Rivera
Aaron Small
Tanyon Sturtze
Chien-Ming Wang
Jaret Wright

Catchers (2)
John Flaherty
Jorge Posada

Infielders (6)
Mark Bellhorn
Robinson Cano
Jason Giambi
Derek Jeter
Tino Martinez
Alex Rodriguez

Outfielders (6)
Bubba Crosby
Hideki Matsui
Ruben Sierra
Gary Sheffield
Bernie Williams
Tony Womack (can also play Middle Infield)