In what is a huge blow for the Baggies, Dike was Ismael's number one target this month – with the club landing him a £7million deal on the first day of the transfer window.
But the American – brought in to end the team's struggles in front of goal – injured his hamstring less than an hour into his full debut against Peterborough.
And without another natural goalscorer in their ranks, Albion will now try and bring in another centre forward before the transfer window closes.
"It's clear that we needed to assess the situation again and see what we can get on the market," Ismael said after confirming Dike's injury.
"We got our target number one, we spent the money on target number one.
"We need to have someone who can help us straight away and for a short time. It’s a balance to find someone who is available and who it makes sense to do.
"We have a couple of days now to make the right decision. First there is a game against Preston.
"But it’s clear that after the game we need to work behind the scenes and put every solution on the table."
Asked if he has a specific target in mind, Ismael said: "No because it’s a new situation, since yesterday.
"We have had a lot of phone calls to see what names we can put on the list – to see what is on the market.
"It doesn’t mean we will do something. I think we have to be careful and think about exactly what we need.
"We have got our target number one, we spent a lot of money on him.
"It could only be a short-term deal, it will have to be a player who can help us straight away.
"We cannot afford to have another two or three weeks for a build-up because there are so many games in the Championship.
"Is it possible to get that player? Is he available? We will see."
Ismael admits it is a huge blow to lose Dike – who is likely to miss 11 games.
"He was a big hope, he was our main transfer, it's a big hit for us," the Frenchman continued.
"The good thing is that he is our player, he has a long-term contract so we will have a lot of joy with him just not in the next 11 games.
"We will start the rehab with Dike and I think if everything goes right he will be available after the international break at the end of March.
"We need to deal with the challenge, we will deal with the situation.
"It was a negative point from Saturday’s game but we took a lot of positive things from the game and that is what we want to take into the Preston game."