Occasionally serf is in favour of eviscerating teammates and their endeavours (7)
I believe the answer is:
efforts
'endeavours' is the definition.
('effort' can be a synonym of 'endeavour')
'occasionally serf is in favour of eviscerating teammates' is the wordplay.
'occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
'is in favour' becomes 'for' (as in being for a particular cause).
'of eviscerating' suggests removing the centre (I've seen 'eviscerated' mean this (the word is disembowelled of its inside letters)).
'teammates' with its centre removed is 'ts'.
The alternating letters of 'serf' are 'ef'.
'ef'+'for'+'ts'='EFFORTS'
'and their' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for efforts that I've seen before include "Acts of trying hard" , "Determined attempts" , "Exertions" , "Endeavours, attempts" .)