One in eight, say, added to half of that in pitcher? (7)
I believe the answer is:
thrower
'pitcher?' is the definition.
(I know that pitcher can be written as thrower)
'one in eight say added to half of that' is the wordplay.
'one in eight say' becomes 'rower' (I can't explain this - if you can you should believe this answer much more).
'added to' is a charade indicator (letters next to each other).
'half of' means to take half the letters.
'that' with half the letters taken is 'th'.
'rower' after 'th' is 'THROWER'.
'in' is the link.
Can you help me to learn more?
(Other definitions for thrower that I've seen before include "who offends the umpire?" , "shyer" , "One who intentionally loses" , "tosser" , "participant in discus event?" .)