The Chelsea man has been first choice in the position for a decade and has won 98 caps for his country, but has come under pressure in recent weeks from his Everton counterpart, who has excelled so far this season for both club and country.
Indeed, the Everton man has started England's last four matches, and Jagielka believes that his club-mate is currently the form player in the Premier League.
"It is going to be a really tough decision for the manager," Jagielka told reporters.
"Getting to watch Bainesy from a closer view than most, he has had a fantastic start to the season at club level and international level.
"It is not a bad headache for the manager to have. You've got Cole on 98 caps, a fantastic left-back, and then you've got the in-form player in the Premier League in Leighton Baines.
"As far as the manager goes he is going to have a bit of a headache but it will be a nice headache."
Jagielka went on to dismiss claims that he may have split loyalties for the crunch qualification clash in Warsaw on Tuesday night after the 30-year-old was initially eligible to play for Poland via his grandparents.
"I've answered the questions before," he explained. "I've got Polish roots but I was born and bred in England. I don't speak that much Polish. It's a game for England and I'll be dying to get the right result for my country.
"It means a bit more with the heritage and stuff but, as far as I'm concerned, it's all about getting another cap and another win.
"We can talk afterwards about where the family is from."