Young believed - prior to the announcement - that Warnock had a great chance of being selected after seeing him excel in the new-look back four.
He told AVTV: "I am delighted for Stephen. I spoke to him before the squad was announced and I told him I thought he had a great chance of being involved.
"This is one of the last couple of squads before the team is announced for South Africa so I hope he impresses.
"I just think he's been excellent since he's been here. The amount of blocks he's got in is incredible.
"He's played really, really well and thoroughly deserves his call-up. I am really pleased for him."