Gordon D'Arcy's hamstring injury may have forced his hand, but O'Sullivan is adamant that the O'Driscoll-Horgan axis - used to good effect twice last autumn, against South Africa and Argentina - will come to the fore against the World champions.
"Once we knew Gordon wasn't going to make it we went back to the formation we had in the autumn with Shane playing at 12 and Kevin moving to the bench," said O'Sullivan today.
"It worked well so it wasn't a difficult decision. I think Shane and Brian are a better combination than Kevin and Brian. Shane did a really good job against South Africa and Argentina. We can call on Kevin as an impact player. The decision is consistent with our recent selections."
Horgan has excelled for Leinster in recent months, finishing the Heineken Cup pool stages as the competition's top scorer with seven tries, but boasts a poor return of two touch downs in his last 16 Ireland Tests.
However, Sunday's RBS Six Nations tie is a heartening eighteenth consecutive outing in green, for the 28-year-old Drogheda man.
With Munster's Denis Leamy injurying his hamstring in action for Munster against Glasgow on Sunday, O'Sullivan conceded: " "Denis wasn't available, so that narrowed the options down. Johnny did play well against Scotland and he knows the English team because he faces their players on a weekly basis.
"Sunday will be a good game for him to play in. The back row is not a done deal but Johnny has done a good job at openside."
Galway-born O'Connor - set for his fourth cap - added: ""I thought I did well against Scotland, and I did what I had to do. Whatever I targeted came off for me so I thought I'd be in with a shout for starting again."
"England's back row is a very talented one indeed. Joe (Worsley), Lewis (Moody) and Martin (Corry) are a good combination and it will prove to be a bit of a challenge for us this weekend. They're very good players but I'm looking forward to it," added the 25-year-old.