Upright piano kept inside also got damaged (8)
I believe the answer is:
goalpost
'upright' is the definition.
(goalpost is a kind of upright)
'piano kept inside also got damaged' is the wordplay.
'piano' becomes 'p' (musical abbreviation).
'kept inside' means one lot of letters goes inside another.
'damaged' is an anagram indicator.
'also'+'got'='alsogot'
'alsogot' anagrammed gives 'goalost'.
'p' placed within 'goalost' is 'GOALPOST'.
(Other definitions for goalpost that I've seen before include "one unfairly moved" , "One propping up the bar" , "One of four supporters at ends of pitch" , "Upright with net attached" , "woodwork" .)