Vokes has returned to Wolves this week.
"Sam will go back to Wolves, but we will be making a call to see how the land lies," Howe told the Lancashire Telegraph. "Obviously losing Martin, we may well reassess that, but we're in Wolves' hands.
"They (the injuries) are a massive downside for us. It could force our hand to look into the transfer market.
"Martin looks like a hamstring strain and these things are usually six weeks, although from our point of view, and from Martin's, it is positive as it's not his thigh. I am really disappointed for Junior too. He's been getting better and better and we can see in training all the time how he is progressing."