Bobby Valentine's likely final season with the Chiba Lotte Marines of the Japanese Pacific League has already been quite memorable, and that trend continued Thursday, when his offensively challenged club erupted for 15 runs in one inning.

In their 23-2 win over the Hiroshima Carp, the Marines sent 20 batters to the plate in the sixth inning to set a Japanese professional baseball record for runs in a frame. Thursday's outburst eclipsed the previous mark of 14 runs in an inning.

The Marines, who entered the game ranked last in their league in batting average (.250) and runs scored (207), had 12 hits in the sixth inning alone, including 11 singles.

Valentine is in his seventh season with Chiba Lotte and is enormously popular with the team's fan base. After club management declared the former Rangers and Mets manager's contract would not be renewed for 2010, Marines faithful began holding nightly vigils outside Chiba Marine Stadium. The fans have also reportedly collected more than 50,000 signatures on a petition to keep Valentine.

"It's an amazing thing," Valentine told The Associated Press earlier this season. "I find it hard to put into words what this means to me. These fans decided this is what they are going to do and they go out and do it. These are people with jobs: executives, students, housewives. It's an incredible thing."

Valentine won 1,117 big league games with the Rangers and Mets, and he led New York to the National League pennant in 2000.