Danny Cipriani and Mike Catt were involved in a training ground incident immediately before the World Cup squad was announced, the RFU have confirmed.
The Sale fly-half was left out of England's World Cup squad as one of the final cuts in Stuart Lancaster's selection, with George Ford and Owen Farrell the only fly-halves included.
However it has since emerged that Catt and Cipriani had a disagreement on the training pitch the day before the squad was announced, although the RFU deny that there was a mutiny within the squad.
"Danny and Mike were involved in a robust conversation on the training pitch following a misunderstanding around a training drill instruction. Both shook hands afterwards and the incident played no bearing on selection," said an RFU spokesman.
England's hopes of reaching the quarter-finals of the World Cup were ended by Australia on Saturday, and they now have just a dead rubber against Uruguay remaining this weekend.