Ancient linesman in short film chasing ball (4)
I believe the answer is:
ovid
'ancient linesman' is the definition.
(Roman poet, someone who wrote lines)
'short film chasing ball' is the wordplay.
'short film' becomes 'vid' (short for video).
'chasing' says to put letters next to each other.
'ball' becomes 'o' (letter resembling a ball).
'vid' after 'o' is 'OVID'.
'in' is the link.
(Other definitions for ovid that I've seen before include "Classical poet" , "Roman poet N void (anag)" , "Void for old Roman poet" , "Metamorphoses author" , "Roman known for his love poetry" .)