WALES wing Hallam Amos won’t make his return from a shoulder injury for at least another month and Newport Gwent Dragons must also cope without speedster Ashton Hewitt in Glasgow this weekend.

Amos has been out of action since suffering an injury while attempting to score against Australia at Principality Stadium in November.

The 22-year-old had initially been targeting a February comeback after going under the knife but is now unlikely to be back before the April 8 encounter with Zebre in the Guinness PRO12 at the earliest.

“Hallam is making good progress and we will decide in conjunction with the Welsh Rugby Union when he will return to play,” said elite performance manager Huw Bevan. “We’re optimistic that we will see him before the end of the season but I would suggest it’s unlikely for March.”

His fellow wing Hewitt is also on the sidelines with a head injury suffered in the defeat to the Ospreys at Rodney Parade on New Year’s Day, although he could be back for the March 24 home meeting with Ulster.

The 22-year-old was forced to withdraw from the Six Nations squad after receiving his first Wales call-up following some livewire winter displays.

“With a head injury you have to be careful and there are protocols that you have to follow,” said Bevan.

“Player welfare is at the forefront of our concerns. He is improving but hasn’t quite managed to complete the full return to play protocol.

“It’s just going to be a matter of time and because he is making progress everybody is optimistic and positive that he will return shortly.

“He’s not far away but it’s very difficult to judge how long it will take to be back to 100 per cent.”

Scrum-half Tavis Knoyle will miss Saturday’s trip to Scotstoun Stadium with a wrist injury while full-back Carl Meyer also sits it out after failing to pass his return to play protocols following a blow to the head against Leinster.

The Dragons are also without lock Cory Hill as the 25-year-old will not be released from the Six Nations squad because Rob Howley's side start their preparations on Sunday morning for the round four clash with Ireland in Cardiff.

Hill, who was a replacement against Italy and England and travelling reserve in Scotland last weekend, was sent out for game time against Connnacht a fortnight ago.

However, with the Irish encounter taking place on a Friday night he has been kept in camp along with colleagues from Cardiff Blues and the Scarlets because their regions play on Saturday.