Team's regulars were introduced to six-footer (5)
I believe the answer is:
emmet
'six-footer' is the definition.
(I've seen this before)
'team's regulars were introduced to' is the wordplay.
'regulars' indicates alternate letters.
'were' becomes 'me' (I am not sure about this - if you are sure you should believe this answer much more).
'introduced' suggests taking the first letters.
The initial letter of 'to' is 't'.
The alternating letters of 'teams' are 'em'.
'em'+'me'+'t'='EMMET'
Can you help me to learn more?
(Other definitions for emmet that I've seen before include "Grockle" , "Insect" , "Hill-dweller" , "one holidaying in Cornwall" , "Local six-footer" .)