The Scarlets have been unable to undertake a full assessment of the injury because of the amount of swelling around the ankle.
Easterby is fortunate that he can still call upon an all-international back row for their RaboDirect PRO12 clash with Treviso in Blues-bound Josh Turnbull, skipper Rob McCusker and Scotland's John Barclay.
But Easterby couldn't help but admit his concern over Shingler's current predicament.
"It is going to be medium to longer-term injury," Easterby told the South Wales Evening Post.
"He has got quite a lot of swelling and we can't make any judgement on that until that has gone down and he is reassessed again.
"But he is in a pretty crappy place at the moment. He has been unlucky."
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