The dynamic midfield duo are considered favourites to pair up at centre for the British & Irish Lions tour of New Zealand this summer and their fitness will come as a relief to Sir Clive Woodward who is using the current Six Nations championship to run the rule over his Lions prospects.
O'Driscoll and D'Arcy missed Ireland's second match of the championship against Scotland at Murrayfield due to hamstring injuries picked up in the opening-weekend victory over Italy in Rome.
O'Sullivan said: "I don't see any reason why Brian and Gordon won't be fit.
They have a lot of hard work to do in the next two weeks and they will be working harder injured than if they were fit.
"That is going to be a very physical match but the boys are going back to Lansdowne Road, which has been a good hunting ground for us.
"It is going to be a phenomenal atmosphere and we are looking forward to the England game."