Howe thinks the forward can still rediscover his best goalscoring form and make Gareth Southgate's playing party for the tournament in Russia next year.
"I think in some respect he will understand, in respect, it's not a competitive game," Howe said on Defoe's demotion.
"I think he will look at it and think he has every opportunity if he performs for us. He will still see that prize at the end of the season. I think it's up to us, and to him obviously, to put him in that position to be able to do it."
Defoe has struck only once for Bournemouth this season.
"I don't think it's about Jermain to be honest," Howe admitted on the Cherries' lack of cutting edge. "It's about us as a team.
"This season if there's been a criticism of the team, we've scored six goals, it's not enough. We haven't created enough chances with regularity, we've not been potent enough in the final third.
"So that's not about Jermain it's about the team.
"Jermain had a slight hamstring problem that took him out of training for about 10, 11 days. So the plan to play him against Chelsea [last game] was for about 60 minutes maximum, anyway.
"Jermain is fine. I think he'll have a big part, [have] a voice in our season.
"He's already scored a very important goal, he's had other chances to score and, again, the team has to create and be able to supply him with the chances that he needs.
"That's been the big thing from the team's perspective we haven't quite done that yet.
"We haven't quite done that this season with the regularity that we've always done it. So, from a team's perspective, we need to find ways to score."