Carrick suffered an ankle injury just before Van Gaal flew into Manchester after guiding Netherlands to third place in the World Cup, but he has been impressed with the new coaching staff.
"It was literally his first day in the office when I went for my operation, so that was shocking timing really," said Carrick.
"But he was great with me straight away, the boss. He has been great, and his staff. They have been really supportive from the first day and I have a lot to thank them for because he had a lot on his plate coming in.
"He took his time to make sure I was all right and getting on the right track."