Saints star Courtney Lawes is winning his battle with a knee injury and is expected to start England’s clash with South Africa at Twickenham on Saturday.
Lawes was a late withdrawal from two Saints matches - against Montpellier and Gloucester - last month due to bruising on the joint.
He had been given until Tuesday to prove his fitness for the Old Mutual Wealth Series opener.
But the 27-year-old’s recovery has progressed well and he is set to resume his World Cup second-row partnership alongside Joe Launchbury in the injury-enforced absence of Maro Itoje and George Kruis.
“Courtney has taken part in training this morning (Monday) and will take part in training this afternoon so we expect him to be fit,” defence coach Paul Gustard said.