Having lost case, simply with no case to lose (8)
I believe the answer is:
misplace
'lose' is the definition.
(to misplace something is to lose it)
'having lost case simply with no case' is the wordplay.
'having lost' indicates anagramming the letters (the original order is lost).
'with no case' says to take the centre (outside letters form the word's case).
The middle of 'simply' is 'impl'.
'case'+'impl'='caseimpl'
'caseimpl' is an anagram of 'MISPLACE'.
'to' is the link.
(Other definitions for misplace that I've seen before include "Mislay" , "Wrongly put - lose" , "Lose - limp case (anag)" , "Be unable to find" , "Lose temporarily - put in wrong location" .)