Slip fielding is not a specialized position. Anyone who can catch well can be there. However, that person has to be alert 100% time of his fielding. Just a minor lapse would undu all the countless hours of slip fielding practices that one may go through.
Captains usually puts himself and his most concentrated fielders in there. Speaking of our captain....
The Weak can never forgive. Forgiveness is an attribute of the Strong." - Gandhi.