The 30-year-old Dragons star suffered the injury during his country's training week in France.
Head coach Gareth Jenkins, who was otherwise pleased with his side's preparations in their camp near La Baule, southern Brittany, said on the Welsh Rugby Union's official website, www.wru.co.uk: "The only negative is that Stephen Jones has pulled a muscle in his groin which will probably keep him out of next week's game against England."
Jenkins added: "There were a couple of other bumps and bruises but nothing too serious and we will know more after we return home."
After Saturday's Twickenham clash, Wales complete their World Cup preparations with Millennium Stadium encounters against Argentina (August 18) and France (August 26).
Their World Cup Pool B campaign begins against Canada on September 9
Wales were due to return home today after finishing off their French trip with a training match yesterday afternoon.
Jenkins said after the 35-minute game: "The training match went very well and was played in the right spirit, we got a lot of things out of the it. In particular, the level of contact needed.
"This match was not about selection, it was about continuing the process and I was pleased with the way the boys reacted.
"Overall, the decision to come to Brittany and train before the Rugby World Cup was the right thing to do. That has become obvious. The hotel and training facilities are first class.
"The players really embraced the week, they were outstanding, we got a lot of work done and their reaction to the week was very positive for our first week back in rugby training and contact.
"What was also pleasing was that thousands of local people came to watch the training match which just goes to show how the locals in the area have embraced us."