The 22-year-old's decision follows a shock first-round defeat by Stefanos Tsitsipas at the US Open, where he had been seen as one of the leading contenders after winning his first ATP Masters 1000 title at the Cincinnati Open in August.
After missing much of 2025 with a lower-back stress fracture, Fils returned to competition in February and enjoyed a strong run of form, reaching the quarter-finals of eight tournaments and winning the Barcelona Open in April.
"After a physically challenging year and several periods of inactivity, I need to be cautious at the moment," the French number one posted on social media.
"Together with my team, we've decided to carry out a full assessment before resuming training and preparing for the rest of the season.
"Representing France means the world to me, so it's never an easy decision to make."
France face Canada in Davis Cup Qualifiers Round 2 from September 18th to 19th in Quebec City.