Aspas, who joined Liverpool from Celta Vigo in the summer in a £7million deal, has lost his place in Brendan Rodgers' side after starting the season in the first XI.
The 26-year-old has yet to score in six appearances for Liverpool and he admits he is finding it difficult not playing on a regular basis.
Aspas is confident he can force his way back into Rodgers' starting XI and in the process try and win a place in the Spain squad.
"I'm finding it hard to be a sub at Liverpool having started games in the past few years," Aspas told Marca.
"When I left Celta Vigo I was aware that to start for Liverpool wasn't going to be easy. And now the team is winning and we are among the leaders in the Premier League, it's very hard to get a game.
"I hope to carry on working hard and little by little to get more game time with Liverpool. I want to change the current situation.
"Now it's difficult to get in the Spain team because I'm playing less but I'm not worried about that. However, I will try to get in the squad."