For sure at 34 he doesn't have the legs he used to when they won the 2005 Champions League in Istanbul. Carrying the Reds almost single-handedly for several seasons will wear you down. And I don't think it's reasonable to expect him to keep on doing that to compensate for weaknesses elsewhere in the team. They could have adjusted their game to keep him playing as a deep-lying midfielder like 35-year-old Andre Pirlo is for Juventus.
I'm not too impressed either by the recent signings of Brendan Rodgers. The Reds have been playing some really sloppy football recently. At times it seems they can't even manage some really basic passes.