Versatile left-wing back and forward Vinagre pulled up in the 1-0 FA Cup defeat at Manchester United on Wednesday night.
Nuno would not reveal a time-frame but says the Portuguese ace will be out for 'some time' as he explained 19-year-old Giles' return from League One side Shrewsbury Town.
He said: "It has to do with the injury of Vinagre.
"That is a massive blow for us.
"Vinagre is very special for us.
"He gives us something that we need."
Adama Traore also pulled up at Old Trafford but Nuno said he was 'OK' when asked about his fitness.
And the Wolves chief confirmed that Vinagre would be undergoing a MRI scan this afternoon to determine the extent of his hamstring injury.
He said: "He will have an MRI today.
"To see the extent of the injury.
"But it will be some time.
"He felt it at the end of the game.
"He was running, high speed running and he felt something."
Giles is expected to start on Wolves' bench for Saturday's Premier League clash at Southampton.
And the Wolves boss expressed his thanks to the 19-year-old for returning to Compton Park.
He said: "We recalled him because we trust him.
"First of all, we have to thank him because he comes to help.
"He comes to help."Hopefully he will improve and he can help boost competition.
"He went to Shrewsbury and did well."Now he is here."He still has a lot of things to improve, but the talent is there."