- Alex Ferguson has confirmed that both Wayne Rooney and Nani will make their comebacks against West Ham, though Jonny Evans is definitely out.
- Ashley Young is also a doubt after suffering a knee injury against Liverpool, while Vidic also picked up a knock late on and is unlikely to feature.
- United needed van Persie to save the day in the last game between the sides and it remains to be seen the strength of team that Ferguson will field.
- Sam Allardyce revealed that James Collins suffered a hamstring tear against Sunderland at the weekend, so Tomkins will take the place of the man whose two goals earned a replay against the league leaders.
- Elsewhere Dan Potts should continue at left-back in the absence of O'Brien and McCartney, with Demel keeping his place on the right.
- Both Mark Noble and Mo Diame could return, with the former missing the game at the weekend with a calf injury, while Allardyce must decide whether Joe Cole is fit enough to play two games in quick succession.
- United will hope to take the confidence from the win over rivals Liverpool into this game against a West Ham side whose morale may be low following defeat at Sunderland.
- Both managers are likely to rotate players for different reasons, with Ferguson hoping to keep some players fresh, while Allardyce will encourage those that didn't feature at the weekend to prove their worth.
- Though United left it late to force a replay last weekend they should be strong favourites to progress past a West Ham side that have been dismal on the road this season.