Rafael Nadal has withdrawn from the Rotterdam Open after being advised to give his troublesome back problem time to heal.

The world number two was scheduled to represent Spain in next week's tournament at Rotterdam Ahoy but has been replaced by Reilly Opelka of the United States.

Twenty-time grand slam winner Nadal has been struggling with a lower back injury and was also forced to pull out of Spain's ATP Cup ties this month.

The 34-year-old was cleared to take part in the Australian Open, where he did not drop a set before losing to Stefanos Tsitsipas in the quarter-finals.

However, Nadal has still not fully recovered from the issue and will now miss another event.

Organisers of the ATP 500 tournament confirmed the news on Thursday and Nadal later took to Twitter to explain the decision.

"It is with great sadness that I have to forfeit from Rotterdam," he said. "As most of the fans know, I suffered some back problems in Australia that started in Adelaide and continued during Melbourne. 

"We found a temporary solution that allowed me to play without pain in the second week of the tournament. Once I got back to Spain I visited my doctor and together with my team they've advised not to play this upcoming week. 

"I was really looking forward to coming back to Rotterdam and The Netherlands since it's been a while I played there this was the perfect year for my calendar. 

"I hope to come back and play there soon. All the best to the tournament, always a top-class event."

World number three Daniil Medvedev will replace Nadal as the top seed in the Rotterdam tournament, which runs from March 1-7.