Spaniard Nadal, a 22-time Grand Slam singles champion, has been plagued by injuries in recent years.
After pulling out of last year’s French Open he said he planned to retire after the 2024 season but on his return in Brisbane suggested he may continue if fit.
His match against Italian 21-year-old Flavio Cobolli on Tuesday in Barcelona, where he has won the title a record 12 times, will be his first on clay since winning the final of the 2022 French Open.
His return this week does raise hope of him competing next month at Roland Garros, where he has won 14 of his major titles.
“It means a lot to me to be able to play one more time here in Barcelona, a place that I have amazing success and a lot of unforgettable memories,” he said.
“So, I am just trying to enjoy every moment and I am excited about being on court in a professional tournament again, especially here at home.
“I was not able to spend a lot of days on tour over the last two years, so I just want to enjoy every day I am able to play with the guys on a professional level. That means a lot for me.”