Fielders that may be brought to book? (4,5)
I believe the answer is:
slip cover
'fielders that' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'be brought to book?' is the wordplay.
I cannot quite see how this works, but
'be' could be 'cover' (covering is a kind of being) and 'cover' is found within the answer.
The remaining letters 'slip' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'may' is the link.
(Other definitions for slip cover that I've seen before include "hard-wearing jacket" , "what new book is in" , "What book goes into" .)