VIDEO: England's Youngs set to miss Wales clash
Youngs was carted off less than 10 minutes into a resounding 46-15 win for the holders in their first game of the tournament at Stadio Olimpico on Sunday.
The scrumhalf was distributing the ball from the base of a ruck when he was tackled by an opposing player and went down in agony.
England head coach Jones does not expect the playmaker to face Warren Gatland’s side at Twickenham next Saturday and said he will undergo tests on Monday.
"He’ll get an examination tomorrow. But he’s unlikely to be available for the Wales game," said Jones.
"I’m always optimistic. It’s a knee injury, it looks like a ligament,"
Anthony Watson and Six Nations debutant Sam Simmonds scored two tries apiece, while Owen Farrell, George Ford and Jack Nowell also crossed for the holders.
Scores from Tommaso Benvenuti and Mattia Bellini had kept the Azzurri in it, but England added three tries in the last 13 minutes to run away with it.
Italy head coach Conor O’Shea said: "I’m proud and angry. I’m proud because I think we saw a team that has a lot of potential out there for the future and played some really good rugby against a great side. We were up against the number two side in the world and we caused them a lot of problems.
"I hate sitting here because we’ve lost and it’s another statistic but in terms of where this team can go and what we were creating, it’s another step forward,"
