St. Louis, MO (My Sportsbook) - With one final opportunity to strengthen his case for winning the NL Cy Young award, Curt Schilling takes the mound for the struggling Arizona Diamondbacks today in the finale of a three-game series against the St. Louis Cardinals in a battle between first-place clubs at Busch Stadium.

Arizona manager Bob Brenly made the decision to start Schilling today once the San Francisco Giants won last night. Since the Giants are just three games behind the D'backs in the NL West standings, Brenly wanted to have his best pitcher on the mound.

Schilling did some damage to his Cy Young hopes in his last start, when he was ripped for eight earned runs on 14 hits over 7 1/3 innings in a 9-4 loss at Colorado. He had been 2-0 in his previous three starts, after allowing eight runs through 22 innings.

The veteran righthander lost his only start against the Cardinals this season. On April 17, he yielded six runs on nine hits over six innings in an 8-4 loss. For his career, Schilling is 5-8 with a 4.44 ERA.

In 16 starts on the road this year, he has gone 12-2 with a 2.98 ERA.

Countering for the Cards is Garrett Stephenson, who is 0-3 in his last six outings. The 30-year-old righthander has made two relief appearances in his last two outings, working two scoreless innings. He last started on September 2, and surrendered five runs on nine hits over 4 1/3 frames in a 5-3 loss to Cincinnati.

Stephenson faces the Diamondbacks for the first time this season. Lifetime, he is 2-1 with a 4.00 ERA versus Arizona.

At home, Stephenson is 1-3 with a 5.60 ERA in seven games (six starts).

In Tuesday's game, Edgar Renteria singled in the game-winning run in the bottom of the ninth inning as the Cardinals edged the Diamondbacks, 3-2. J.D. Drew snapped an 0-for-22 slump with a solo homer for the Cardinals, who have already won the National Central Division title and will likely face Arizona when the NLDS gets underway next week.

Junior Spivey was 2-for-4 with an RBI for the Diamondbacks, who have lost five straight. However, Arizona clinched a postseason berth with Los Angeles' 1-0 loss to Colorado on Tuesday. The D'backs have a magic number of three to seal the NL West over San Francisco, which defeated San Diego. Arizona is three games ahead of the Giants with five games remaining for both teams.

Arizona received bad news earlier Tuesday, when it was announced that All-Star leftfielder Luis Gonzalez will miss the rest of the season, including the playoffs, with a separated left shoulder. Gonzalez suffered the injury Monday night in a collision in left field .

Albert Pujols still needs four RBI to become the first player since Joe DiMaggio to have 260 RBI in his first two seasons.

Mike Fetters (3-3) was dealt the loss, allowing one run in two-thirds of an inning. John Patterson started for Arizona and allowed just one hit, while striking out eight and walking two in six scoreless frames.

Jason Isringhausen (3-2) blew a save in the ninth, but wound up posting the victory. Andy Benes pitched seven scoreless innings, surrendering four hits and two walks, while striking out four.

St. Louis leads the season series, 3-2. Arizona is 43-37 on the road this season, including 2-6 on a current nine-game trip, while St. Louis brings a 48-28 home record into this contest.