Without a service record you won't for sure.
He may have been wounded & posted back to France with the 9th. as an administrative transfer because he was transferred the following day to the 19th.
The war diary is at the TNA. It doesn't mention him by name but you will see what they were up to around June 1917.
http://www.rootschat.com/links/01j9t/ &
The 1/19.
http://www.rootschat.com/links/01j9v/ You can download them for £3.45.
I can tell you from the 1/12 diary they were at Arras April 1917 involved in that battle.
They drove the Germans back to beyond Wancourt (E. of Arras) by May 1917.
The 1/12 held that position (under almost continuous bombardment) until relieved on the 15th. May when they went into Bde. & then a few days later Div. reserve where they remained past the 16th. June 1917 when your man returned to the UK.
He may well have been wounded but 4/6 weeks seems a long time from arriving at a CCS to evacuation but not impossible.