Leeds United and Sunderland are interested in 18-year-old forward Woodburn while Aston Villa have been linked with midfielder Grujic, 21.
Both players have found game time difficult to come by this season.
Woodburn has made just one appearance in the EFL Cup while Grujic has featured six times in all competitions.
Young forward Harry Wilson has also been linked with a loan move to the Championship with Preston interested.
Klopp wants his prospects to get regular first-team football.
But he admits all three are unlikely to leave next month.
“We will see,” Klopp said. “These boys are all really close, much closer than you can see when I do the squad.
“We have to decide at one point if it makes sense that they stay. For a lot of them, it makes sense that they stay here because we need them. For a few, maybe it makes a little bit less sense.
“We will see and nothing is decided so far. We will see which clubs are asking and then we have to make a decision whether it is good for the boy or not and all these things.
“But, really, for most of them there will be no transfer window. They will stay here.”