Blockhead is joining Eliot, perhaps, in seconds (7)
I believe the answer is:
assists
'seconds' is the definition.
'blockhead is joining eliot perhaps' is the wordplay.
'blockhead' becomes 'ass' (I've seen this before).
'joining' is a charade indicator (letters next to each other).
'eliot perhaps' becomes 'ts' (TS Eliot).
'ass'+'is'+'ts'='ASSISTS'
'in' is the link.
(Other definitions for assists that I've seen before include "Provides" , "Lends a hand" , "Contributes to success" , "Aids" , "Helps or waits on" .)