The 23-year-old former Basel and Bayern Munich star watched from the stands at the Britannia Stadium as Stoke lost their Premier League opener 1-0 to Liverpool.
"We are hopeful, but we have had a pre-season of chasing really quality targets," said Hughes.
"We hope we can do something but until we see players standing in front of the training ground with the Stoke shirt in their arms you don't know."