"We are thinking," the Dutchman told reporters at his pre-match news conference ahead of Wednesday's Premier League clash with West Bromwich Albion.
"We have to have good competition, good double occupation in every position... but we must not go into this danger when something happens with one or two strikers.
"I don't deny that it would be a concern if Costa or Remy were injured."
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Chelsea have recently been linked with a number of strikers, including West Brom's Saido Berahino, but Hiddink refused to be drawn on potential targets.
"The window opens and the mouth shuts," he said.
"I have good contact here with the technical board and others. They are open to discuss all the options. That does not say it has to be done or it's done but it's open.
"I am thinking. And it's not good talk when you are thinking in this case because, why shall we go public? If, suppose something is going on, it can be harmful when you go public."
(Reporting by Simon Jennings in Bengaluru; Editing by John O'Brien)
