The 22-year-old needed lengthy treatment following a hefty challenge from Denmark's Liverpool defender Daniel Agger during the first half of the 1-0 win at Wembley.
Wilshere was substituted after an hour, and replaced by Southampton's Adam Lallana, whose cross set up Daniel Sturridge for a late headed goal to finally beat Kasper Schmeichel, the Leicester goalkeeper.
There was, though, no major injury scare for a player set to be crucial to Arsenal's run-in, which continues with an FA Cup quarter-final against Everton on Saturday.
"It is a bit sore, but just a bruise. I have had a scan already and I will be alright," Wilshere told reporters.
The Arsenal midfielder hopes solid club form can now secure his golden ticket to Brazil as part of Roy Hodgson's final 23-man squad.
"We have all been working hard in training trying to impress the manager, but at the end of the day, it is your club form which will get you in," he said.
"These next two months are crucial, it is a big time of the season and then when the England squad is announced, you can only perform to the best of your ability."
Hodgson, meanwhile, insisted Wilshere - who has been a through a string of injury setbacks - was never scheduled to play the whole match.
"It was always the plan to replace him just after half-time, not least of all because Arsenal have some important games coming up, a lunchtime kick off (against Everton on Saturday) and then Munich (away in the Champions League)," the England manager said.
"We had that in mind not to keep him on the field for too long.
"The kick made that more obvious as a decision.
"I was a bit concerned when he went down. It was a nasty one. It was a 50:50 and they both went for it.
"I hoped it was a bruise rather than anything more serious, and it was.
"I am hoping when he goes back to Arsenal tomorrow he will be fine."
Sturridge had started on the flanks as part of a fluid front three alongside Wayne Rooney and Liverpool team-mate Raheem Sterling, before moving into a more central role following changes in the second half.
Rooney, replaced by fellow Manchester United forward Daniel Welbeck on the hour, felt the experiment had been worthwhile.
"We play a different system with me, Daniel and Raheem more interchanging a little bit, and I thought it worked quite well, (but) obviously there is room for improvement," he said.
So long England's talisman, Rooney would be many people's first choice to lead the World Cup attack.
However, the 28-year-old will not rest on his past achievements.
"This was the last game before the manager names his squad, there was 29 of us here and we all wanted to show what we can do - that is from me through to everyone else, we all want to show him what we can do." he said.
"I am sure the manager has got a bit of thinking to do now. He has got some tough decisions, but that is what he is here for, to make them."