NPB announced Friday it has finalized Tohoku Rakuten Golden Eagles infielder Japhet Amador's six month doping suspension after investigating the issue following his appeal.

Amador, who denied knowingly taking any banned substances, offered his explanation on Sept. 4. But NPB decided to go forward with the ban handed down on Aug. 9 for testing positive for two drugs, chlorthalidone and furosemide.

The Eagles had filed an appeal on Amador's behalf on Aug. 22 to seek further investigation into the circumstances in which the Mexican slugger took the substances, which can serve as masking agents for performance-enhancing drugs.

The 31-year-old, who had been batting .269 with 20 home runs over 62 games this season, tested positive for the two drugs following an exam on June 13.

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