Marin is starting to see action after recovering from injury at the start of the season.
He told chelseafc.com: "After my start with the injuries I came back and was again injured but now I feel better, nearly 100 per cent fit, and we can see it with the playing time, I've started to play and now I'm involved I hope it will continue.
"The important thing is minutes. I can only get fit with minutes in the games. Training does so much but matches are the best thing.
"The Capital One Cup is an important title. Every player in England has an aim to play in Wembley, because it means you have done well, and this is a big chance for us. We are in the semi-final and we want to win.
"Winning a title in February is early, and we still have the FA Cup too, so it can help us in the league, where it will be tough, but maybe we will have a chance."