The 33-year-old reflected on being omitted from the starting XI against Chelsea last Sunday - the first time he has missed an important game when available for 11 seasons.
He told the Telegraph: "I am not the future of Liverpool. Daniel Agger, Martin Skrtel and Sebastian Coates are. But I can still be part of the present for a few more years. It's only one game I've not been selected so it's not the end yet.
"Over the last decade if I had missed a match I would have gone straight back into the team when available. This time I didn't and I have to accept it, agree with it and understand it. I was out for a couple of weeks and the lads who came in did really well. I've always said mental strength is important in every player and this is another test of that.
"In the past there were people saying if Steven Gerrard and me weren't playing there was a problem, but now you look at it and say out of the last three games we've won two away from home. That's good for the club. We have to look to the future. I'm sure the manager, Damien Comolli and owners are looking at that while wanting to make sure we're doing everything to win from one week to the next. I think I can speak for Stevie too when I say we're desperate to help the club win trophies as much as we can, whether we play all the games or not."