The Chelsea captain retired from national-team duty after being suspended for racial abuse by the Football Association and Jagielka has since partnered Blues star Gary Cahill at the heart of the Three Lions' back line.
Despite Terry's decision to step back from England and manager Roy Hodgson's unquestioning acceptance of that fact, the 31-year-old has been followed by questions on the subject.
|11/4||England are 11/4 with PaddyPower to be beaten to nil by Italy at the World Cup|
"Our defensive record in the qualifiers was pretty decent but I can't stop what people are going to ask. I just have to put on a smile and keep going.
"I can't say I particularly like hearing it but I understand why it comes up. Gary and JT play together at Chelsea, they play in the Champions League and were contenders to win the Premier League.
"I've always said that partnerships are important – if you have the choice of two players who work better together, or two who are thought of as better defenders, you're better off sticking with the two who know each other's game. I can understand why people are saying it. I can't control what people say."
With friendlies against Peru, Ecuador and Honduras to come before the Three Lions get to business in Brazil, Jagielka is keen to push himself to full fitness after a late-season injury as well as re-establish his partnership with Cahill.
"I still find it difficult assuming I'm going to play for England," he continued.
"I've played quite a lot in qualifying and I have built up a good relationship with Gaz. We haven't played together for a little while and hopefully the next three games will give us the chance to get that relationship going again.
"[I'm] not 100 per cent sharp – hopefully if I can get some time on the pitch in these next three games I'll soon be a lot fitter."
Uruguay, who will face England in the group stage, are sweating on the fitness of Liverpool star Luis Suarez after post-season surgery but Jagielka says that they must be prepared to face the PFA Player of the Year.
"We will have to prepare as if he makes it," the centre-back declared. "Uruguay have not qualified just because of what Luis Suarez has done but he can make a massive difference. He's the player of the year and I have lost track of how many goals he has scored and set up.
"If Uruguay can't have their best players it is a bit of a bonus but we can't put our hopes into him not making it. We have to think he will be there."