Defoe missed the recent international friendly matches against the Netherlands and Italy, having only returned to full fitness after a serious ankle injury.
The 35-yera-old now has his confidence back after stepping off the bench on Saturday to rescue a point for Bournemouth in a 2-2 draw with Watford.
He was involved in the qualifying campaign for the tournament in Russia, but has since lost his place in the team.
Defoe has managed only four goals this season, but is adamant that getting more game time and scoring regularly could help him secure a ticket to the global showpiece.
"I came here (to Bournemouth) as an England player. I worked so hard to get back in the squad and signed here as an England player," he told Sky Sports.
"I have missed the last three squads because I am not playing. I spoke to the manager a few months ago and it's as simple as that, you have got to be playing and scoring goals and see what happens.
"It's not up to me, it's up to the manager. We will see what happens. I understand I have got to be playing, you can't just assume you're going to get in the squad because of what you have done over the years.
Onc"You have got to be playing, you have got to be performing and you have got to be scoring goals. Once I start doing that I will feel I'm ready to go now.
"At a tournament, it is not just about the players who start, it's about the squad. It has been a stop-start season for me but I can't sulk. You have to be professional and come on and make an impact."
The 35-yera-old now has his confidence back after stepping off the bench on Saturday to rescue a point for Bournemouth in a 2-2 draw with Watford.
He was involved in the qualifying campaign for the tournament in Russia, but has since lost his place in the team.
Defoe has managed only four goals this season, but is adamant that getting more game time and scoring regularly could help him secure a ticket to the global showpiece.
"I came here (to Bournemouth) as an England player. I worked so hard to get back in the squad and signed here as an England player," he told Sky Sports.
"I have missed the last three squads because I am not playing. I spoke to the manager a few months ago and it's as simple as that, you have got to be playing and scoring goals and see what happens.
"It's not up to me, it's up to the manager. We will see what happens. I understand I have got to be playing, you can't just assume you're going to get in the squad because of what you have done over the years.
Onc"You have got to be playing, you have got to be performing and you have got to be scoring goals. Once I start doing that I will feel I'm ready to go now.
"At a tournament, it is not just about the players who start, it's about the squad. It has been a stop-start season for me but I can't sulk. You have to be professional and come on and make an impact."
