The 36-year-old Spaniard played his last-16 clash at the All England Club on Monday against Botic van de Zandschulp with strapping across his abdomen.
Only last month, he won a 14th French Open with his troublesome left foot anaesthetised before undergoing career-saving treatment.
Nadal refused to discuss whether or not his latest physical concern is a worry.
“I’m a little bit tired to talk about my body, all the issues that I am having. I prefer to not talk about that now,” said Nadal.
“All respect for the rest of the opponents. For the moment I am healthy enough to keep going and fight for the things that I want.”
Nadal is halfway to the first calendar Grand Slam by a man since Rod Laver in 1969.
After needing four sets in each of the first two rounds to progress, Nadal has since looked impressive, sweeping past Lorenzo Sonego and Van de Zandschulp to make the quarter-finals for the eighth time.
On Wednesday, he will seek to reach the semi-finals, also for the eighth time, when he faces in-form Taylor Fritz.
The American is in the last eight of a Slam for the first time and has yet to drop a set.
The 24-year-old defeated Nadal in the Indian Wells Masters final earlier this year when the Spaniard was suffering from a cracked rib.
‘Play freer’
That defeat ended his 20-match win streak and forced him to take a six-week rest before the clay court season.
Fritz, whose mother played Wimbledon in 1977, said facing Nadal meant all-out attack.
“I don’t really second-guess shots like I would if I’m playing someone that I’m supposed to beat,” he said.
“I might think like, Should I go for this, should I play it safe? Against someone like Rafa, it’s easy to always make the aggressive decision and play freer.”
Waiting in the semi-final will be either controversial Australian Nick Kyrgios or Chile’s Cristian Garin.
Despite the presence of Nadal and six-time champion Novak Djokovic in the draw, Kyrgios has arguably been the headline act.
He is back in the Wimbledon quarter-finals for the first time since 2014 when he made a mockery of his 144 world ranking to stun Nadal.
The 27-year-old has made the quarter-finals having played two five-setters, thrilled and confounded spectators while picking up $14,000 in fines.
He has also showcased some breathtaking shot-making, taking his aces count past the 100 mark and hitting a total of 257 winners over four rounds.
