There were doubts about whether Jagielka would be available for the tournament after he struggled to recover from a hamstring injury he suffered in February.
The Everton defender was sidelined for two months towards the end of the campaign, but he returned for the final two matches and he is now nearing full fitness after an intense week-long training camp with England in Portugal.
"Last week was important for me to get a few more sessions under my belt," Jagielka said after a training session at St George's Park on Tuesday.
"We had a really good session today and it is about getting myself ready.
"I do not need to be 100 per cent fit this week, it is more about building up and getting match practice before we go out to Miami. Hopefully I will time it perfectly for the opening group game."
Many perceive England's defence to be their weak spot, but the Three Lions conceded just four goals in qualifying.
Hodgson will also be comforted going to Brazil knowing that England have not lost a game when Cahill and Jagielka have started together.
That statistic has meant Jagielka is now integral to Hodgson's plans, unlike two years ago when the 31-year-old was an unused squad player in Euro 2012.
Jagielka thinks his game has come on a lot since then, partly due to the fact that he was named Everton skipper at the start of last season.
"Being made Everton captain this year forced that on me a little bit more," said Jagielka, who started seven World Cup qualifiers.
"I am quite loud and vocal on the pitch. It is important we have leaders in all different types of areas.
"I am not guaranteed to play but I am in a better position than I was two years ago. I have played a decent role in the qualifying campaign to get us to Brazil and it would be nice to get some game time and be part of a successful England team."
England play Peru at Wembley on Friday before heading to Miami for a week-long training camp which includes games against Ecuador and Honduras.
"It is all about momentum. If we can get some decent results in the friendlies we have got before the tournament, we can get some confidence going," said the defender, who has 24 England caps.
"The lads are really positive and we have got some fantastic players. People may be playing down our chance, but momentum is a fantastic thing in football."
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- Roy Hodgson
- Gary Cahill