Band's unexpected statement cut short (4)
I believe the answer is:
blur
'band's' is the definition.
(English band)
'statement cut short' is the wordplay.
'statement' becomes 'blurb' (I have seen 'Promotional statement ' mean 'blurb' so perhaps 'statement' could also mean 'blurb').
'cut short' means to remove the last letter.
'blurb' with its last letter taken away is 'BLUR'.
'unexpected' acts as a link.
This may not be right. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for blur that I've seen before include "Obfuscate" , "Become unclear" , "Out-of-focus image" , "Unfocused image" , "Group - smudge" .)