Rafa’s whole career has been injury plagued, IIRC an injury kept him out of the 2004 French Open. So sustained healthy physical state has never been in the cards for him ever.
It’s different now because so many of his earlier timeouts centered around the chronic foot issue which aggravated his knees. Now it’s more the actual body wearing down (ribs, stomache tear, hip) and yes, he’s turning 37.
Having said that Rafa is not Roger. There actually is less wear and tear from tournament use than Federer had; in Federer’s case I think all that tournament play just grinded down his knees, that streak of consecutive Slams accumulated had to have consequences.
John Isner is still playing now at age 37 and within his career capacity and there are more players having extended careers in all sports. So a 37or 38 year old Nadal could have some flashes of brillance left in him for intermittent periods, certainly I hope for some fortnights. Plus in mental age he’s still 25 so until he hangs it up I’m hoping for a few more streaks of the magic.
This is a good point. Clearly Rafa has had to deal with a lot of injuries, but this is
partially balanced by him having more time off court. In all sports, there's a common and direct correlation between longevity and grinding wear and tear. Some athletes - and really, both Rafa and Roger are two of them - have tremendous longevity. But even with them, father time takes its toll - and it isn't absolute years, but relative ones.
I'm reminded of the recent fasting craze. One of the benefits is that evidently it slows, even reverses, the aging process (to a small extent). Digestion takes a lot of energy, and giving it a rest - whether through daily intermittent fasting, once a week full days, or occasionally long-term fasts, it gives the whole body a rest, and in turn activates autophagy, which is the body's self-repair mechanism.
So while dear Kieran will always want to shine the best possible light on Rafa so that the implication is that if not for bad luck he'd have won 30 Slams (haha), the other side is that his injuries have given his body more rest and maybe extended the duration of his career - and also allowed him to "surge back" multiple times. Meaning, it balances out somewhat (to what degree is debatable).
As for the future, Rafa will turn 37 in a few weeks having played 305 events and 1303 matches (plus the hundreds of matches he played before going pro). When Roger turned 37 in 2018, he had played about 350 events and 1450 matches...so about two full season's worth more.
Roger's big comeback in 2017-18 was short-lived, but he remained a very good player for another couple years, reaching the AO Slam SF in 2020 at age 38 - about a year and half older than Rafa is now. I see no reason why Rafa can't -- on a purely physical and skills level -- comeback to at least a very competitive form (i.e. the guy to beat on clay, at least, and very good elsewhere). But it really comes down to health, and how much more his body can take. I mean, he could come back and have a great summer, then one tweak in August and he's out again, and I have to wonder how many more times he wants to come back.
So if I were a betting man, I'd guess that he'll give it one more go and play as long as he can stay healthy, but if and when he gets hurt again, he'll hang up the racquet and focus on fishing and fatherhood and boning Xisca on his boat (I mean, I would!).
Oh, and as I said upthread, from a purely tennis standpoint, I'd really like to see him (in good form) face Alcaraz at RG. It would be epic, I think.
