Newcastle expect to formally announce Holland international Daryl Janmaat as their fifth summer signing on Wednesday.
The 24-year-old Feyenoord full-back travelled to Tyneside on Tuesday to undergo a medical and discuss personal terms after the two clubs agreed a fee at the weekend.
It appeared an announcement was imminent with a photograph of the player holding a back and white shirt alongside Magpies manager Alan Pardew appearing on Twitter later the same day.
However, some minor formalities remain to be completed and that means Janmaat will not now be unveiled until Wednesday.
His official arrival will be significant for more than one reason as it is likely to trigger Mathieu Debuchy's departure for Arsenal.
Dutchman Janmaat will become Pardew's fifth summer signing and the second this week after Remy Cabella joined Siem de Jong, Jack Colback and Ayoze Perez at the Magpies.