Wilshere, 19, was at the centre of a tug of war between Arsenal and England over his end-of-season schedule.
Asked if Wilshere looks tired, Terry replied: "You know what, he doesn't. But he's played 60 games this season and it's his first full season.
"I see him as a major part of the senior set-up. If we're looking to the Euros next year, we have to nurture him and he has to be looked after.
"It's been a big issue and I had a quick chat with him about it.
"He's a confident young man and is obviously disappointed that he's not going with the Under-21s but, at the same time, he feels part of the seniors.
"I honestly feel we need to look after him rather than make him feel we're against him and make him feel comfortable in his decision.
"Not everyone is going to agree, but what he's shown for us in the last few games has been incredible.
"Not many of us expected him to step up the way he has done. For him to be fresh and keep stepping up next year is going to be important.
"Everyone was keen to see fresh faces and fresh players come in, and he's been the one who's stood out from everyone so we need to look after him.
"Hopefully he can have an injury-free season next year and be ready for the Euros.
"For the senior England team it's a great thing that he'll have a rest."