The Magpies do not expect to see Merino back on Tyneside for pre-season training on Monday, and the deal could be completed soon.
“Until it becomes official, no, and I think it still has not been finalised," Garitano replied when asked if Sociedad had completed the signing of Merino on Radio Euskadi.
"It could be a good signing for us. He has been at important clubs like Borussia Dortmund and Newcastle - and, at the age of 21, he has a great future ahead of him. We hope it can be completed."