His position is so crucial for our gameplay and he lacks a lot to make us function the way we are accustomed to now.
It would have been less of a problem if he was a top attacking RB all his career and was just only starting to decline because of age.... but the problem is that he was never a natural world beater on his flank like sandro is... and he compensated with energy and effort. Now all that is fading away with age and he cant even control the ball or run properly, much less add to the attack.