Wales’ back three options are limited with Rogers ruled out of the England game after suffering a fractured thumb.
His fellow wing Josh Adams sustained a hamstring injury in training and has not featured since the opening two Six Nations games.
Full-back Liam Williams was ruled out of the tournament after sustaining a knee injury in the competition opener against France.
Sherratt opted not to call up any reinforcements this week with Cardiff full-back Cameron Winnett and Dragons wing Rio Dyer overlooked for this campaign.
Gloucester wing Josh Hathaway was the only specialist squad option remaining but Sherratt has opted to utilise Roberts out of position and put Saracens centre Tompkins on the bench.
Roberts, 24, has made 32 starts at centre for Scarlets, although he has made the odd replacement appearance on the wing.
“Getting the chance to wear the shirt in any position is a huge honour,” said Roberts.
“I have never really started the game there but have a bit of experience. Early on when I first started to play for Scarlets, when I was on the bench and you have the likes of Jonathan Davies and Johnny Williams there, I would come on the wing.”
Roberts was exposed to 70 minutes last weekend when Rogers was forced off.
“There is always a chance it can happen being on the bench so I prepared for it during the week but you never think it will happen that early,” said Roberts.
“It went all right. I made some errors not being used to playing there as often but I enjoyed it. It was nice to have the ball in a bit of space and it was a bit of a change.”
