Try followed by team's first red card (5)
I believe the answer is:
heart
'red card' is the definition.
(I've seen this before)
'try followed by team's first' is the wordplay.
'try' becomes 'hear' (as in to try someone in court or hear their case**).
'followed by' is a charade indicator (letters next to each other).
'first' says to take the initial letters.
The initial letter of 'teams' is 't'.
'hear'+'t'='HEART'
(Other definitions for heart that I've seen before include "Nucleus" , "Centre; core" , "Not a club" , "Muscular organ - compassion" , "It beats" .)