For Marion, it's win on the road or close out the season with eight straight losses, including two in the postseason. A win at Riverside Park on Thursday would keep the series there for the final game on Friday. The Bobcats were only 1-4 in Dawson Springs this year.
O'Brien was 2-2 in the regular season, but led the league in strikeouts and threw six innings of one-run ball in his last start, which was Marion's last win on July 21 against Owensboro.
Thursday's game begins at 7 p.m.
Elsewhere, Owensboro will be looking to punch their ticket for the championship with a win at Fulton on Thursday. The Oilers took Game 1 on Thursday by a score of 6-5.
