After again making the postseason in 2011 with a 58–38 record, but again falling to River City in the Division Series, Southern Illinois made the playoffs as a wild card entrant at 55–39, finishing one win ahead of Windy City and the Schaumburg Boomers. The Miners faced the Traverse City Beach Bums, who finished with the league's best record at 64–32, in the division series. In Game 1 on the road, the Miners shut out the Beach Bums 1–0 behind a solo home run by postseason all-star outfielder Javier Herrera (acquired in a trade with the Rockford RiverHawks earlier in the season) and eight shutout innings from ace right-hander David Harden. In the second game, Traverse City scored three runs in the first inning and led 4–0 in the sixth before the Miners came back with three runs in the sixth and a game-tying RBI single by Cory Harrilchak in the eighth inning. With the score still tied at 4–4 in the tenth inning, outfielder Ken Gregory hit a go-ahead solo home run, which eventually proved to be the winning run in a 5–4 Miners extra-inning victory. Southern Illinois completed the sweep of the favored Beach Bums by winning Game 3 at home 4–3, sending the club to their first-ever Frontier League championship series.