Trump went on to say that he has not set any official timetable for the US withdrawal, and that the times being talked about elsewhere didn't come from him. This started weeks ago with talk of a 30 day drawdown, and has since been in the four month range. 

CNN claimed that the four month figure came from the Pentagon, with an unnamed official saying it was the military "trying to please the President and not get everyone killed." He added that the Pentagon should keep troops in Syria even longer. 

This of course, is all in keeping with the narrative among the Pentagon brass, most of whom never wanted to leave Syria at all. The idea that it would take four months minimum to remove 2,000 troops from eastern Syria, however, does not make a lot of sense.