Barkley, 20, continued his superb first half of the season with a stunning free-kick to give Everton a 2-1 win at Swansea on Sunday, adding to growing calls for him to be granted a World Cup place next summer.
His performance only added weight to the view that England manager Roy Hodgson cannot ignore the midfield starlet when it comes to selecting his squad for the summer finals in Brazil.
Jagielka, himself almost certain to be part of that England squad if fit, knows there are plenty of obstacles for Barkley to navigate yet, but knows his team-mate can thrive for club and country if Everton ensure they give him the means to perform.
Jagielka said: "All he's got to do is keep putting his name into the hat.
"He has not got that much experience but on the other hand he has got a hell of a lot of ability.
"It's which one you choose, but at the moment he is in great form and if the World Cup squad was being announced tomorrow you'd like to think he would be in it.
"There's a long way to go between now and then.
"Ross needs to know he needs to stay injury free and keep up the form he is doing. It's up to us to keep him going.
"He's not a lad that will get carried away with himself, he's a fantastic lad.
"Sometimes if things do go wrong for you in a few games, confidence can quickly evaporate but it's up to us to keep him at the level he is at.
"If we can do that it will only be beneficial for England but first and foremost for Everton."
Everton will look to keep their unbeaten run of 10 games going when they face Sunderland and Southampton in back-to-back home games over the festive period.
And Jagielka wants Everton to show they can handle the increasing expectations of their fans as they battle for a Champions League spot.
"It's going to be a tough little period with the amount of games and the number of points on offer," he said.
"It's important we try and get as many points as we can and see where it takes us in the new year.
"Getting six points is definitely the plan but we know it's going to be difficult.
"The games you are expected to win, especially at home, can sometimes be the harder ones.
"The games without the expectation can sometimes be the easier to play in.
"We know because of the position we have put ourselves in people will expect us to get close to maximum points, at least four points, over the next two games to keep ourselves in the mix of the top four."