Kepa has impressed since stepping in for the injured Edouard Mendy.
After their 3-0 Champions League win against AC Milan, Kepa told AS: "Obviously I've been there (Spain) a long time and when you're not there you miss it. It is in my head and hopefully I can come back soon.
"I can't tell you that (if I can make the World Cup squad) because it's a question for him (coach Luis Enrique), but I'm sure it's easier playing than not playing.
"I work for that, for when the coach needs me and like against Milan to try to respond and win games."