Emerton returned to action last season from a nine-month lay-off due to a knee injury.
The 31-year-old has recently been linked with a move to Galatasaray.
“It’s been frustrating for Brett, but I think this season is going to be the one where he will show his full potential again,” said Allardyce.
“I do think the trauma of an injury that big at his age shocked him.
“But it hasn’t from a physical point of view as he’s never been so fit. Hopefully, those injuries are put to one side now.”