He does not have to enter Ihram [at that point]. If the one who is doing Tamattu` does `Umrah, then goes out from Makkah to At-Ta’if or Jeddah or Madinah, then comes back, he does not have to enter Ihram for Hajj (yet), because he has come back to the place of residence.
As he has come as a pilgrim, Makkah is regarded as the place where he is staying, so if he travels to Madinah then comes back, he has come back to the place where he is staying.
Therefore, he should enter Ihram for Hajj on the day of At-Tarwiyah [i.e., 8th Dhul-Hijjah] from Makkah, as if he is one of the residents of Makkah who went to Madinah during the months of Hajj, then came back from Madinah having the intention to do Hajj this year. So he does not have to enter Ihram for Hajj from anywhere other than Makkah. (End quote from Majmu` Fatawa Ibn `Uthaymin, 22/78)
For a fuller explanation, see these answers: (40512, 40356, 12239, 196976, 42507)
And Allah knows best.
