PARIS — Rafael Nadal has a chronically injured left foot that sometimes hurts so much he cannot play.
A stress fracture in one of his ribs, suffered at Indian Wells in March, cut short his clay-court season and has left him with far less preparation than usual ahead of his favorite tournament, the French Open.
His knees are often on the edge of balky. He is two weeks shy of his 36th birthday, an age that, a generation ago, would have effectively stopped him from contending for, much less winning, Grand Slam titles. He limped through the final set of his last match, a three-set loss in the round of 16 at the Italian Open.
And yet, as Alexander Zverev, the world’s third-ranked men’s tennis player, watched Nadal practice Thursday morning — because even the best players in the world will stop and watch Nadal hit any ball at any time on the red clay of Roland Garros — Nadal’s vulnerability was not on his mind.