BRISBANE (AFP) - Spanish superstar Rafael Nadal insisted on Tuesday (Jan 1) he is not chasing the world's top ranking as he prepares to make a comeback from ankle surgery, with taking care of his body a key priority.

The current world No. 2 has not played a main tour event since a knee problem forced him to retire during his US Open semi-final against Juan Martin del Potro in September.

The 32-year-old had surgery on his ankle in November to remove a loose intra-articular body and only resumed training three weeks ago.

He played the opening round at an exhibition event in Abu Dhabi last week, where he lost to South African Kevin Anderson, and gets his season proper under way in the second round of the Brisbane International on Thursday.

The 17-time Grand Slam winner said he had not been worried about the world rankings for the past two years.

"My goal is just to be happy doing what I am doing and be competitive all the weeks that I am playing," he said.

"I want to feel myself competitive every week that I am on court and I want to keep fighting for the things that really make me feel alive, you know, for the things that motivate me.

"So I will not (chase) the number one because it's not my main goal.

"Of course, I prefer to be number one than number two, and I prefer to be number two than number five, that's obvious," he added.

Nadal was forced to retire during matches at two of the four Grand Slams in 2018, but still added a record-extending 11th French Open crown to his collection.

He said he wanted to ensure he could take care of his body to allow him to keep playing as long as possible because of his love for the game.

"The thing that I don't want to do is suffer more than what I did last year, because if you do (suffer injuries two) years in a row, that mentally kills you," he said.

"I really believe that I have to keep having tennis to play in my career, and I really feel that my body is not going to get worse every year.

"Really my only goal is to keep doing the things that makes me happy, and today playing tennis makes me happy, and I want to do it the best way possible and as long as possible."

In the second round Nadal will play either Jo-Wilfried Tsonga of France or local hope Thanasi Kokkinakis, two players who have also been troubled recently by injuries.