At this point, it's a toss up between the Orix Buffaloes and the Seibu Lions. If the Buffaloes win tomorrow, they'll finish the Inter-league season in first place. If the Buffaloes and the Lions win, the two teams will be a in first place tie with 15-9 records. Based on the current rules, the tiebreaker will go to the Lions because they finished with a better record during last year's Inter-league season.
Incidentally, the team to finish in dead last has already been decided: Yokohama Bay Stars.
For the third year in a row, the Bay Stars will finish the Inter-league season in last place. With two more Inter-league games to play (tomorrow and a make-up) they could end up with the most losses during Inter-league play since the Buffaloes ended the season with 24 back in 2006. And that's when the Inter-league season was still 36 games long.