In case the article included is the minimum (5)
I believe the answer is:
least
'the minimum' is the definition.
(thesaurus)
'in case the article included' is the wordplay.
'in case' becomes 'lest' (I've seen this before).
'the article' becomes 'a' (indefinite article).
'included' indicates putting letters inside.
'lest' placed around 'a' is 'LEAST'.
'is' is the link.
(Other definitions for least that I've seen before include "Lowest amount" , "Smallest in amount or degree" , "Opposite of most" , "Steal (anag)" , "Being lowest in importance - gone stale" .)