Put under, one may start as provisional (7)
I believe the answer is:
interim
'provisional' is the definition.
(I've seen this in another clue)
'put under one may start' is the wordplay.
'put under' becomes 'inter' (I've seen this in another clue).
'one' becomes 'i' (Roman numeral).
'start' says to take the initial letters.
The first letter of 'may' is 'm'.
'inter'+'i'+'m'='INTERIM'
'as' is the link.
(Other definitions for interim that I've seen before include "not there for ever" , ", I'm put in grave situation initially" , "Meantime; temporary" , "Temporary - provisional" , "acting" .)