The winger, who is on a year's contract with the Scarlets and Wales' Sevens had scored two tries in the Premiership fixture before sustaining a fracture and dislocation to his neck at the game held at St Helen's.
He was taken immediately to Morriston Hospital and then later transferred to the Heath hospital in Cardiff where he has undergone three operations.
Scarlets Head of Medical Andy Walker said: "Mike underwent a third operation at the Heath Hospital on Sunday and is doing well.
"The operations have stabilised his spine and Mike is now on the road to recovery and was discharged from hospital on Tuesday. We will continue to monitor and review Mike's condition over the coming weeks.
"Once again, on behalf of Mike, his family and the Scarlets we would like to express our gratitude to all the staff and medical teams at both Morriston and Heath Hospitals for their excellent work as they continue to monitor him."
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