Jogger welcoming a rest (9)
I believe the answer is:
remainder
'rest' is the definition.
('remainder' can be a synonym of 'rest')
'jogger welcoming a' is the wordplay.
'jogger' becomes 'reminder' (I've seen this before).
'welcoming' is an insertion indicator (in sense of 'inviting in').
'reminder' placed around 'a' is 'REMAINDER'.
(Other definitions for remainder that I've seen before include "book going cheap" , "that's left" , "Left-over" , "deposit" , "Unsold copy of book" .)