Is the play in the fore-aft direction or the side-to-side direction?
If fore-aft, adjust the front and rear bushing tension to eliminate the slop.
If side-to-side, the plastic/nylon bushing on the side is probably worn and needs to be replaced. Unfortunately, that bushing isn't sold as a standalone part; it only comes as part of the entire shifter assy. There is an aluminum replacement that will eliminate all side-to-side play (Function First) but its somewhat expensive.
FUNCTION-FIRST > Shift-Right Solution
I have Ben's short shifter with the Function Five kit and there is no play or slop in any direction.