Indeed Tevez is still good enough to play, but the statistics are to decline in my opinion. Now he could only score a few goals and I think his stamina has decreased not like before. If you see news, Tevez claimed he was tired and he intends to retire early. I look at some of the interview, Tevez still confused about his future, and he is confused to accept the Chinese club.
I think thats because Argentine League is not too competitive for him, thats why he feels bored and considers to retire. Anw he is still 32 yo, which its not too old for a player as good as him. Well its up to him tho, he has full right to do what he feels best for himself.