The call-up of 21-year-old Simpson means there are now three scrum-halves in the 33, while Hodgson joins fellow fly-halves Toby Flood and Jonny Wilkinson.
In the injury-enforced absence of Jonny Wilkinson and Toby Flood, uncapped Leicester fly-half Sam Vesty and Brive's Andy Goode were selected ahead of Cipriani for the senior squad.
Wilkinson was set to challenge Leicester's Toby Flood and a fit-again Danny Cipriani for the number 10 shirt under new manager Martin Johnson, but that scenario is now likely to be delayed.