Striking opener faces the bowler with seam exposed, getting stumped (2,3)
I believe the answer is:
at sea
'stumped' is the definition.
(I've seen this before)
'striking opener faces the bowler with seam exposed' is the wordplay.
'opener' indicates taking the first letters.
'faces' is a charade indicator (letters next to each other) (some letters face or go next to others).
'the bowler' becomes 'at' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' is a charade indicator (letters next to each other).
'exposed' says to take the centre (the inside of the word is exposed).
The centre of 'seam' is 'ea'.
The first letter of 'striking' is 's'.
's' put after 'at' is 'ats'.
'ats'+'ea'='AT SEA'
'getting' is the link.
Can you help me to learn more?
(Other definitions for at sea that I've seen before include "Where a packet might be" , "Sailing off shore" , "Disorganised; bewildered" , "Confused, uncertain" , "Where Corcoran was hardly ever sick" .)