Both limped off during Northampton’s 16-6 loss at home to Saracens and with England facing a hectic autumn schedule, which includes games against Fiji, Australia, South Africa and New Zealand – Lancaster will be keeping his fingers crossed. 

Of particular concern is the hooking department, with Lee Mears having called time on his international career just a few months ago and Rob Webber missing through injury.

Hartley, who started every game of this year's RBS 6 Nations, was the only capped hooker named in Lancaster’s squad this week, with his only replacement – Leicester’s untried front row-convert Tom Youngs.

With England basing their game on a solid set-piece, the news Hartley could be an autumn casualty will leave a huge hole in Lancaster’s preferred front row options.

Lawes has also been in impressive form for Northampton after returning from injury but with Mouritz Botha, Tom Palmer and Geoff Parling all capable of deputising and all with international caps to their names – it’s Hartley that will be causing Lancaster the biggest concerns.

And Northampton Director of Rugby Jim Mallinder admitted the severity of his international duo was at this time unknown.

"They've done something, but we will know a lot more later," he said.

"They are the sort of characters that if they had just got a knock they wouldn't have come off."