Those who are running maybe abruptly keel over (9)
I believe the answer is:
shortlist
'those who are running' is the definition.
(shortlisted candidates)
'abruptly keel over' is the wordplay.
'abruptly' becomes 'short' (synonyms).
'keel over' becomes 'list' (list can mean to tilt or keel over).
'short'+'list'='SHORTLIST'
'maybe' is the link.
(Other definitions for shortlist that I've seen before include "suitable candidates" , "Ko-Ko had" , "Reduced size of field" , "Final candidates" .)