Puzzled as big athletic fellow initially ran away (7)
I believe the answer is:
baffled
'puzzled' is the definition.
('baffle' can be a synonym of 'puzzle')
'big athletic fellow initially ran away' is the wordplay.
'initially' indicates taking the first letters.
'ran away' becomes 'fled' (I've seen this in other clues).
The first letters of 'big athletic fellow' is 'baf'.
'baf'+'fled'='BAFFLED'
'as' acts as a link.
(Other definitions for baffled that I've seen before include "Confused" , "Frustrated" , "Perplexed" , "Completely mystified" .)