Williams was surprisingly not among the 36 players named by Warren Gatland for the Tests against Australia, Georgia, New Zealand and South Africa.
Wales released a short statement on Wednesday which said: “Tyler Morgan’s ankle injury sustained in the fixture for the Dragons against the Ospreys last weekend will preclude him from taking any part in the Under Armour Series.
“With this in mind he will continue his [injury rehabilitation] management at his region.
“Scarlets centre Scott Williams joined the squad this morning.”
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