I keep telling myself that on the grand scale of mortality, one knee injury doesn’t weigh much. Federer says he wants to play a few more years, and missing a couple of majors doesn’t mean that he won’t be able to do it. It doesn’t even mean that he won’t keep playing at the same near peak of almost greatness he’s occupied since his run of unquestioned dominance over the sport ended — but gently, oh, so gently — in 2009 or so.

Still, this injury feels a little different from the average tennis setback. It feels different even from the average season-scuttling, surgery-necessitating setback that makes you worry a player will never be the same. I’ve been thinking about why it feels different, especially in light of two small but significant Federer occurrences that took place this month.

The first occurrence: Aug. 20 was the 10th anniversary of David Foster Wallace’s essay “Roger Federer as Religious Experience,” which was originally published in The Times’s now-defunct sports magazine, Play. I’ve spent the last 10 years alternately loving and being exasperated by this work, which is probably a sign of all great essays; in any case, it’s the piece of writing that did more to construct the terms in which we now view Federer than any other.

Wallace advances the impossibly ambitious, totally doomed and thrillingly beautiful idea that high-level spectator sports serve an aesthetic and even quasi-spiritual function, namely to reconcile viewers to the limitations of their own bodies. The body ages, breaks down, gets sick, suffers and dies. But when we watch Federer in peak moments, Wallace says, we imagine what it would be like to experience a physical freedom unburdened by pain or weakness, and this in turn helps us cope with the troubling fact of our own mortal embodiment.

After reading Wallace’s description of Federer as “both flesh and, somehow, light” in 2006, it was hard to see Federer as merely a tennis player, even a great tennis player. Even the very best who ever lived. To many fans — including me, at times — he became something more than that. He became a kind of abstract principle, a living avatar of sport’s potential for transcendence.