I think you're being very generous and Rangnick believes in the exact opposite to what you've just said.
"My former clubs were always trying to make sure the rehab should take place in the club itself," said Rangnick.
"As far as I can tell the medical department is really good, very good, with many different approaches towards rehab. I would not want players to do their rehab abroad or anywhere else, but the decision on Paul was taken before I came.
"In the future, and I have already spoken to the medical department, I want players with injuries, and hopefully we don't get long-term injuries, but if we have them in the future I want them to stay here."
I'm with Ralf on this one. His former clubs and now United want players rehabbing at the club.