Barry sustained a groin injury in England's friendly win over Norway and a subsequent scan revealed a muscle tear in his lower abdomen. The Manchester City midfielder, who replaced Steven Gerrard at the interval, lasted less than half an hour before being withdrawn.
Jagielka, who impressed as he played out the full 90 minutes, will effectively give manager Roy Hodgson licence to use the versatile Phil Jones in midfield, rather than as an auxiliary centre-half. Hodgson will submit his definitive 23-man squad to UEFA at midday tomorrow, albeit any enforced changes are permissible up until England's first game.
In addition to Barry's absence, Hodgson still harbours injury concerns over Danny Welbeck and Glen Johnson, while Scott Parker's fitness remains somewhat suspect, despite coming through 55 minutes on Saturday unscathed.
As for 31-year-old Barry, who was touch and go for the 2010 World Cup with an ankle problem, Hodgson insists his international career is not yet over.
"I'm very disappointed to lose Gareth. I'm sure he will still have a part to play with England after the Euros.
"Not only was he a member of my original 23-man squad, but he has featured prominently in the England team over the last few years."
For England, Jagielka's inclusion inevitably prompts more questions than answers, not least why Michael Carrick was initially overlooked. Moreover, Hodgson's decision to call up another defender suggests he is likely to opt for a 4-4-2, with only Gerrard, Parker and Frank Lampard natural fits for a central midfield role, with Jones, James Milner and Alex Oxlade-Chamberlain less tested options.
In all likelihood, Jagielka is going solely as an understudy, with Chelsea pair John Terry and Gary Cahill tipped to start against France. But Jagielka will justifiably point to his performance in the 1-0 win against Spain last November as proof of his international pedigree. England are currently 2.8615/8 to keep a clean sheet against Les Bleus come June 11 and a rather optimistic 2.942/1 to start with a win.