Chelsea and England centre-back John Terry has revealed he has "had a bit of a problem" with his hamstring since the World Cup.
Blues captain Terry will sit out Friday’s European Championship qualifying opener against Bulgaria at Wembley as well as the trip to Switzerland four days later after being ordered to rest for the next 10 days.
The defender told Chelsea TV: "I have had a bit of a problem since the World Cup and I was hoping after the World Cup that I would have two weeks off and it would completely go away.
"But that wasn’t the case and, coming back working hard, it came back on."
Terry has played every game for club and country this season but claims the injury was behind his half-time substitution in England’s recent friendly win over Hungary.
"I played the last England game but I had to come off at half-time because of it," he said.
"I have not made it public but I have been struggling with it and maybe I just need 10 days’ rest to fully get over it because it could impact on my season."
Terry’s injury has not prevented him helping Chelsea make the perfect start to their defence of the Premier League, the champions scoring 14 times in three straight victories without conceding a goal.
The 29-year-old praised his fellow defenders for the shutouts but also singled out holding midfielder John Obi Mikel, who he revealed had shed the pounds in a bid to keep his place in the side.
"John had a really good pre-season and looks slimmer," Terry said. "He has done a bit of weights and really looks fit.
"We have missed Michael Essien the last couple of years and there is competition now.
"I think John feels that with Ramires coming in and Michael coming back, and he feels he needs to step it up.
"He had a great season last year and the season before that but again he has kicked on, which is important for the young players to do."