Many observers thought that Jon would play at No.8 after such a strong season, but Ally Hogg was selected, despite having recent experience at openside.
"In the back row, JP has played seven very well while I feel Hoggy is perhaps better served playing six or eight," said Williams. "JP is perhaps a bit sharper over shorter distances, while Ally has played exceptionally well in the Tests at No.8. It may be when Simon comes back we have to look at it again, but at this stage you want to make the most of the strengths you have."