Yokozuna Kisenosato has been diagnosed with damage to his left chest muscle in addition to the earlier-announced left upper arm injury, the Japan Sumo Association said as it made public his medical certificate Monday.
The document, dated March 27, said a monthlong recovery will be required for Kisenosato, who won the Spring Grand Sumo Tournament in Osaka in March despite being hurt on the 13th day of the 15-day tourney.
His stablemaster, Tagonoura, originally did not mention the yokozuna's pectoralis major injury, suffered during a defeat to Mongolian yokozuna Harumafuji.
Kisenosato is absent from the ongoing regional tour but resumed training Monday in Tokyo behind closed doors. His stable sources said the 30-year-old was able to perform stamps.
Kisenosato won the January tourney and became the first Japanese-born wrestler to win promotion to sumo's highest rank in 19 years. The hope of back-to-back titles last month seemed dashed with the injury, but he defeated runaway leader ozeki Terunofuji on the final day before beating him again in the playoff for a dramatic come-from-behind victory.
Kisenosato became the first wrestler in 22 years to triumph in his first tourney as yokozuna.