A section of football, i.e. division in league (6)
I believe the answer is:
allied
'in league' is the definition.
(thesaurus)
'a section of football i e division' is the wordplay.
'a section of' indicates the answer is hidden within the clue.
'ALLIED' is hidden in the letters of 'football i e division'.
(Other definitions for allied that I've seen before include "Owl's cry" , "Joined for mutual benefit" , "Joined by, eg, treaty" , "United through treaty" , "In league" .)