The Tokyo District Court has sentenced former Yomiuri Giants pitcher Shoki Kasahara to 14 months in jail, suspended for four years, for betting on baseball games and helping a restaurateur to run a gambling ring.

Betting on games by an active player "contributed to ruining the credibility of professional baseball," Judge Yasunobu Hosoya said in handing down the ruling on Wednesday.

Kasahara, 25, had admitted to gambling.

Kasahara's co-defendant, Satoshi Saito, 38, was sentenced to 18 months in jail, suspended for four years, for organizing a betting ring and taking a commission on bets on pro and high school baseball games.

Their defense counsel did not dispute the prosecution's version of events, but argued that since there was no gambling house and Saito communicated with punters via cellphone or email, it meant Kasahara's gambling was the only chargeable offense.

But the court recognized Saito's restaurant in Tokyo was a base for the gambling, and the ruling said "advanced telecommunication technology just made it possible for the defendant (Saito)" to take bets from anywhere.

According to the ruling, Kasahara personally placed bets totaling ¥4.5 million and helped Saito by collecting money for bets placed by two other former Giants pitchers — Ryuya Matsumoto and Kyosuke Takagi — between September 2014 and August 2015.

Saito organized a betting scheme and took a commission on bets on 12 baseball games between May 2014 and August 2015.

In late September, police arrested a senior member of a Japanese crime syndicate and two others for allegedly taking bets on baseball games, including from former Yomiuri Giants players.

The police stepped up their investigation after suspecting the money gambled by ball players helped finance criminal groups.