McFadden was north of the border on a few days' leave from Everton.
He told the Scottish Sun: "It was a very kind gesture by Motherwell and I am grateful to them for letting me train with the boys.
"It was great to catch up with some old friends.
"Everybody made me feel very welcome and it was great to see all the office staff too. Motherwell will always have a place in my heart because the club and the people mean a great deal to me."