The USA international winger has been on Celtic boss Gordon Strachan's radar for 18 months.
"We don't want to stand in anybody's way," said Chivas coach Preki. "If Sacha stays with us, that's great. If he makes it to that level, that's great recognition for the club and we wish him all the best. "Right now, we don't know what's going to happen. We'll just wait and see."