Japanese-born yokozuna Kisenosato, who had been gunning for his third straight title, has withdrawn from the ongoing Summer Grand Sumo Tournament after failing to recover from upper body injuries, sumo officials said Wednesday.

The 30-year-old wrestler from the Tagonoura stable becomes the second grand champion to pull out of the 15-day meet at Tokyo's Ryogoku Kokugikan following Kakuryu, who announced his withdrawal after four days.

Kisenosato lost his second straight bout in a defeat to sekiwake Kotoshogiku on Tuesday as he dropped to 6-4, while the two Mongolian yokozuna -- Hakuho and Harumafuji -- maintained their unbeaten records at 10-0.

On Tuesday, Kisenosato, who had missed just one day of competition since his sumo wrestler debut 15 years ago, was easily bumped out of the ring by former ozeki Kotoshogiku.

After sustaining left arm and left chest muscle injuries on the 13th day of the spring meet in March, Kisenosato rushed his rehab in order to bid for a three-peat, but he has been unable to rely on strength in his left arm since the ninth day of the Tokyo meet.

"After seeing how he wrestled yesterday we decided he should pull out as he is in no condition for decent sumo," his stablemaster Tagonoura said.

"He was desperate but just because he's a yokozuna doesn't mean he should compete under any circumstances. He'll get treated and turn his focus to the next tournament."

Tagonoura revealed that talks were held between Tuesday evening and Wednesday morning, at which time Kisenosato asked for his approval to sit out the remainder of the tournament as he "cannot exert strength," and has felt that way after his eighth bout.

Kisenosato will need to undergo a monthlong treatment, but Tagonoura said it does not mean his injuries have been aggravated. It is rather his awareness of his responsibilities as a grand champion that has allowed him to make the tough decision, he said.

Meanwhile, stablemaster Nishiiwa, who currently serves as coach of the Tagonoura stable, said it was lack of preparation time that forced Kisenosato out of competition.

"He only had about a week to practice against wrestlers before the meet. You would usually train for about a month after healing from injury so I wish he had more time. I hope he will be able to live up to fans' expectations at the Nagoya basho (in July)," said Nishiiwa.

It is the second time in his career that Kisenosato has pulled out of a meet, the previous occasion being the 2014 New Year tournament when he was competing as an ozeki.

Sekiwake Tamawashi, Kisenosato's scheduled opponent for Wednesday, wins by forfeit.