On Friday night, Milwaukee rookie Casey McGehee provided another highlight to a fine rookie season. The Brewers were tied with Houston, 2-2 in the eighth inning, with Prince Fielder on second base and one out. Astros manager Cecil Cooper brought in LaTroy Hawkins, his top setup man, to face McGehee, who laced a single to right field to score the winning run.

One of the biggest surprises of the rookie class, McGehee has been driving in runs consistently since he became an everyday player in mid-June. Although he has mostly played third base in place of the slumping and eventually traded Bill Hall, the rookie also has been able to fill in at second base, a position left vacant in mid-May by Rickie Weeks’ season-ending wrist injury.

After six years in the Chicago Cubs’ system, the 26-year-old McGehee was picked up on a waiver claim by Milwaukee last October. He was coming off a solid but unspectacular season at Triple-A Iowa in 2008, but McGehee has been better than that as a major league starter. And his production has continued into September.

McGehee not only tops all rookies with 61 RBIs this season, he is the major league leader with 21 in September. He is hitting .349/.419/.587 with four home runs in 19 games this month, and he’s a .304 hitter for the season.

With 17 doubles and 15 home runs in 105 games, McGehee is slugging .506 and has an .874 on-base-plus slugging (OPS). Among rookies with at least 250 plate appearances in 2009, only Pittsburgh’s Garrett Jones has higher marks. He’s slugging .589 with a .955 OPS.

A year ago, the rookie looked like little more than a bench player, but he’s made a case for a regular job in 2010. He was bumped from second base when the Brewers acquired Felipe Lopez on July 19, but he’s made most of the starts at third base since then and kept himself in the lineup with his bat.

The next challenge will come from third-base prospect Mat Gamel. McGehee, one of the unexpected success stories of 2009, will have to prove again next spring that he’s more than a minor league lifer.