The club is in discussions with Crystal Palace over a move for the 24-year-old, who starred for England at Euro 2024 this summer.
Asked about Newcastle's interest in Guehi on Thursday, Howe said: 'I'm able to give you nothing.'
'We're slightly light on numbers,' said Howe. 'Emil (Krafth) has done a really good job during pre-season, playing inside from his normal full back position, and he has the capability of doing that.
'We have very good players in there, but, naturally, when you lose those two players for the length of the time that we have, that was a big dent in the middle of our defence.'
The club are in talks with Crystal Palace over England defender Marc Guehi in a deal worth around £65million
Howe has tracked the 21-year-old since Jason Tindall, his assistant, worked with him during his spell on the coaching staff at Bramall Lane.