There will be a sharp intake of breath from the whole of Ireland when Brian O'Driscoll, still the best player in the British Isles and indisputably the finest outside centre of his generation, makes his first tackle on a Frenchman in Dublin this evening.

The three-tour Lion has been struggling with neck problems in recent weeks and is keen to dispel all doubts about his fitness for the forthcoming World Cup campaign by lasting a full game against quality opposition.

France have made 13 changes from the side that beat Ireland in Paris a week ago – only the wing Alexis Palisson and the hooker Dmitri Szarzewski back up – while Ireland have reunited the pack that gave England such a rough ride in the Grand Slam match last March.

Andy Robinson, the Scotland coach, will be looking long and hard at his back-row players in this afternoon's game with Italy at Murrayfield. The senior flankers Kelly Brown and John Barclay are in tandem for the first time since the Six Nations, while Richie Vernon has a precious opportunity to make the World Cup cut at No 8. Robinson says he is looking for "more energy" in attack – a clear indication that his side's lack of creativity with ball in hand remains a worry.

However concerned Robinson might be, it is as nothing compared with the air of anxiety in South Africa. The Springboks have lost all three Tri-Nations matches to date, so today's game with New Zealand in Port Elizabeth has become a win-or-bust affair. The home side have made changes to the spine of their side – Patrick Lambie at full-back, Morne Steyn at outside-half, Bismarck du Plessis at hooker – while the electrifying All Black full-back Israel Dagg has this one opportunity to nail a World Cup place after a spell of injury hassle.

Finally, Pat Sanderson, the long-serving Worcester flanker and captain who was a fixture in the England back row during Andy Robinson's reign as national coach, has reluctantly retired from rugby at 33. He made his decision on medical grounds after failing to recover from a serious shoulder injury suffered last March.