BEIJING, Feb. 22 (Xinhua) -- Olympic and world champion Ma Long announced here late on Thursday that he opted to skip the Chinese national team's trial for April's World Table Tennis Championships due to injury.

It won't be expected to cut short the 30-year-old Grand Slam winner's chance of participating in the championships slated on April 21-28 in Budapest, Hungary.

Ma, skipper of the Chinese men's team, has been suffering the left knee injury since last August, which saw him withdraw from the ITTF World Tour Opens in the Czech Republic, Sweden, Austria, as well as the 2018 men's World Cup in Paris suburb and the year-ending Finals in South Korea.

He also missed most of last season's Chinese Super League matches from the eighth round and so on, citing the same reason.

"I've tried a lot in rehab and see some positive results on my injured knee," Ma said. "But both the medical staff and my coaches of the national squad agreed that we should not take a risk when it came to some old injuries."

"In that case, I made my decision to pull out of the national trial in order to make sure that I'd be in better status to prepare for the worlds in the following massive training camp," he added.

Ma's place in the ITTF world rankings has slipped to the 12th since his consecutive absence from international competitions.

His teammate Zhang Jike, another active Grand Slam winner of table tennis Olympic Games, World Championships and World Cup, also announced earlier to skip the national trial after missing regular training for months.

The February 28-March 3 trial in Shenzhen will decide one men's and one women's singles berths for Budapest 2019, where China, powerhouses of the world table tennis, will have five spots for both men's and women's singles, and two each for men's doubles, women's doubles and mixed doubles.