Ashton also spoke well of Josh Lewsey after he opted for the untested skills of Mark Cueto at full back in place of the 46-cap World Cup winner, following an uncharacteristically low-key display from Lewsey against France.
While Ashton was at pains to stress Lewsey, 30, has an international future, he also had reassuring words for injured Saracens centre Andy Farrell, who has been leap-frogged by London Irish veteran Mike Catt.
Ashton said: "It was a difficult decision to leave Josh out because he has given, and I'm sure will do again, great service to England.
"As for Andy Farrell, when he gets back playing with Saracens we'll assess him and make a decision from there.
"He's come in for some unfair criticism from a lot of people, a lot of whom should know better. He's been one of our most consistent, if not our stand-out performer."
Ashton was also full of praise for London Irish youngster Shane Geraghty's stunning 20 minute debut cameo against France.
Geraghty will again take his place on the bench on Saturday, while Ashton admitted the impressive form of Quins' Academy full back Mike Brown has brought him into the reckoning.
He said: "I didn't think to stick Brown in for his first game at the Millennium Stadium would be the sensible thing to do. The Welsh will be pretty stoked up for this game."
Harlequins No8 Nick Easter has a neck injury but is expected to resume training tomorrow.