The 26-year-old remains the world's most expensive goalkeeper following his £71m move to Stamford Bridge from Athletic Bilbao in 2018, but he has struggled to justify his price tag.
Kepa's error-strewn performances led the club to move for former Rennes keeper Mendy - who has established himself as Thomas Tuchel's number one - and Kepa has now opened up on his frustrating situation at Chelsea.
Speaking to Radio Marca, the Spaniard said: "Everyone wants to play. Everyone wants to be in the starting line up on Saturday and Sunday.
"For outfield players, there's a chance of coming on, but the goalkeeper surely isn't going to play. It's not easy. The game days when you don't play aren't easy.
"You need to assume your role at that point. Help as best you can. During the week, on a daily basis, push to the maximum. Doing it for you, not for anyone else, just to be prepared. To keep improving and to be ready when given the opportunity or for any circumstance."
Kepa boasts 40 clean sheets from 110 games in a Chelsea shirt and remains under contract with the Champions League holders until the summer of 2025.