A scan is understood to have revealed Itoje suffered a grade two medial ligament tear that usually requires up to four weeks of rehabilitation.
Sarries team-mate Nick Isiekwe has been called up in Itoje's place, while uncapped quartet Jack Singleton, Ben Earl, Dan Robson and Ollie Thorley are part of the squad.
Either Courtney Lawes or Joe Launchbury will slot into the starting XV in his absence, partnering George Kruis in the second row.
"Maro's going to be the best lock in the world so it's a big loss, but we've got good depth", Jones said.
"He's a brilliant player and he's a world-class player", England scrum-half Danny Care, who missed out on selection for Eddie Jones' squad, told Rugby Union Weekly. "We always look at different combinations and we'll be doing that over the next few days".
Itoje saw a specialist on Monday to be given a clearer picture of when England can expect him back.
The 24-year-old played 53 minutes during the tournament opening game against Ireland at Aviva Stadium last weekend before limping off the field.
England's players were allowed to return home on Sunday afternoon and Wilson found himself looking after his two children rather than basking in a hero's welcome in his home town of Newcastle.