I'll go with Alex Cintron or Tony Blanco. Tony Blanco literally did nothing to remembered for other than JimBo having a hard-on to his tools.
Those are really good suggestions.
As a Pitcher Antonio Osuna ERA 40.00+!!!
That dude was a total bum as well. But as far as a player who had a long stint of suckitude you have to hand it to Kearns and Jesus Colome/Felix Rodriguez/Joel Hanrahan.