Carrier of some oak cask currently being returned (8)
I believe the answer is:
rucksack
'carrier' is the definition.
(something which carries things)
'some oak cask currently being returned' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'being returned' says the letters should be written backwards.
'kcaskcur' is hidden in the letters of 'oak cask currently'.
'kcaskcur' reversed gives 'RUCKSACK'.
'of' is the link.
(Other definitions for rucksack that I've seen before include "Bergen?" , "Back carrier" , "Trekker's baggage" , "part of hiker's gear" , "A hiker's backpack carrier" .)