Tigers captain Youngs, as a hooker, sees at close quarters the work of the men in the No9 shirt, including his brother Ben who has been away with England for the autumn internationals.
In his absence, Harrison and White have taken over in a pivotal role for Tigers and both have also been given added responsibility in captaining the team during that period.
“Ben White, he’s tenacious, he has some spirit about him,” said skipper Youngs.
“He is going really well, you know he’ll get stuck in and with Geordan [Murphy] giving the starts in the team, it builds massive confidence that he is doing something well.
“You’ve also got Sam in there and I think they’re quite similar. They’re both tough guys who never give up. They’re doing a great job.”