The Scarlets scrum-half will compete with Mike Phillips and Lloyd Williams for a spot in the side to face the Springboks on November 9.
And, despite being just 20 years of age, ex Wales wing and current Scarlets assistant coach Jones is convinced Williams won't be intimidated or overawed about mixing with the big boys.
"I have no qualms about him being ready," said Jones.
"He is mature beyond his years and understands how we want to try to play the game. He understands what we want him to look for in opposition defences and what their weaknesses are and he is only going to get better at that.
"Wales are fortunate they have Mike Phillips, who has been a stalwart for them over the years, and Lloyd Williams, who has been in the squad for a while now, but I am sure Rhodri will go in there and mix things up and give the selectors a headache for the Springboks game."
Williams has enjoyed a stunning season so far for the Scarlets, shining in the recent Heineken Cup ties with Harlequins and Racing Metro.
A try scorer in both those high-profile fixtures, the former Wales U20 cap has now firmly established himself as first-choice in Llanelli having earned his spurs in the Principality Premiership with Llandovery.
"What you are seeing now is a maturity in his performances at our level," added Jones.
"With us having numerous good scrum-halves here and having had good scrum-halves here who have since moved on, I think it was the right decision last year to let him go and play semi-pro level to honour his U20 commitments.
"He understands how to run a game better having had lots of games for Llandovery. This season, we were always keen for Rhodri to come in and start competing for that No9 jersey and it just shows if you have a run of games and play well, national selectors are not afraid to pick you."