Both clubs agreed the £3million transfer on January 22 but require special dispensation for the deal to be completed because the striker, 30, has already played for two clubs this season.
Smith said: "The problem we are having is that it's taking so long that his lack of match practice is going to be a problem whichever way the decision goes.
"If he goes to Fulham, they will obviously have the same problems as ourselves at the present moment, that he won't have had sufficient match practice in the last few weeks.
"So, it's beginning to get to that stage where we are going to have to look and see what's best for both parties.
"We can use him just now, he still remains a player we can use. But it's complicated by the fact that, once we have made arrangements to transfer the player and he has gone through medicals at Fulham, it becomes awkward to play him because you take the chance of the player becoming injured.
"It's an awkward situation and not one that we're used to but we are hoping for a resolution shortly.
"It would only be fair from all sides that they do that and let us get on with whatever the decision is.
"If the decision goes against the transfer, then we will have no hesitation in bringing him back and playing him. There is no problem with that."