The influential lock injured his AC joint during Ireland's defeat to France, but following intensive treatment he is now hopeful of being fit for Sunday's RBS 6 Nations clash with Wales at Lansdowne Road.

Ireland team doctor Gary O'Driscoll said: "Paul is now pain free in the shoulder and has progressed at a very pleasing rate. If Paul's rehab continues on this present curve, we are reasonably confident that he will be available for the weekend."

Meanwhile, O'Sullivan has added nine players to his squad ahead of Sunday's crucial encounter.

The additional players will join the 22 who featured in the defeat by France in Paris on February 11.

Marcus Horan (Munster), Mick O'Driscoll (Munster), Matt McCullough (Ulster), Jamie Heaslip (Leinster) and Neil Best (Ulster) are the forwards brought in.

Denis Hickie (Leinster), Girvan Dempsey (Leinster), Robert Kearney (Leinster) and Barry Murphy (Munster) also come into contention for places among the backs.

Munster pair Anthony Foley (ankle) and John Kelly (groin) were not considered due to injury.

Ulster and Ireland A prop Bryan Young has also been called up due to an injury to Reggie Corrigan.

Corrigan suffered a neck strain playing for Leinster against the Newport Gwent Dragons and has been told to rest for 48 hours.