Nippon Professional Baseball said Thursday it has suspended Rakuten Eagles infielder Japhet Amador for six months for a doping violation.

The 31-year-old Mexican slugger, who has been out since Aug. 3 with abdominal pain, tested positive for two banned substances, chlorthalidone and furosemide, NPB said.

Rakuten said it is currently conducting another test after Amador denied taking the substances. Amador has been ordered to stay at home while the Eagles investigate and come up with a possible punishment.

"I've never doped in my entire baseball career. I've never taken banned substance intentionally," Amador said in a statement released by the Eagles.

"I've been tested so many times and I've always been clean. Testing positive this time has come with great surprise, and it worries me very much because I don't recall myself doping," he said. He added he will cooperate with the investigation.

(Amador hits a solo home run against the SoftBank Hawks in Fukuoka on April 18)

The two substances he tested positive for were diuretic drugs used in the treatment of high blood pressure. Diuretics can be used to mask the presence of performance-enhancing substances in the bloodstream.

Amador gave a urine sample following the Eagles' interleague game against the Chunichi Dragons at Rakuten Seimei Park Miyagi on June 13. A drug testing agency reported the positive result on July 23.

At a hearing on July 30, Amador denied knowingly taking a banned substance but did not file an appeal over the test results.

In 62 games for Rakuten this year, Amador posted a .269 batting average with 20 home runs. He helped Rakuten reach the Climax Series last year, batting .237 with 65 RBIs.

He joined the PL club in 2016, a year after leading the Mexican Baseball League in home runs.

Amador is the fifth player to receive a doping suspension since the NPB introduced drug testing in 2007, and the first since 2011.