I really don't know how to answer this. First of all, most of the s*** pitchers that have played for the Sox during my 50+ years of fandom have been purged from my memory, thankfully!
Next, what really constitutes the worst pitcher? A guy who pitches 60 innings one year and is gone? Or a starter that brings futility for 7-8 years?
Of course there are many variants in between.
Dice-K drove me f***ing nuts!!!! I offered to bash his ankles with a bat at one point.
However, I thought it was kind of cool that he tried to hang on with Tito in Cleveland so I harbor far less ill will towards him now.
The Sox have had their share of suck pitching over the years. Fortunately I don't remember most of them!