The Cardinals, though, enter tonight's matchup having dropped three of four after losing two of three to Kansas City over the weekend, but still sit just a half-game back of the Cincinnati Reds in the National League Central.
With the Reds starting a series against Philadelphia, the Cardinals are hoping to take advantage of a Diamondbacks team that is 16 games under .500 and 15 1/2 games back in the NL West. Especially with Carpenter on the hill tonight. The former NL Cy Young Award winner has won his last five decisions and is 9-1 on the year to go along with a 2.63 earned run average.
Carpenter got the win in his last trip to the hill on Wednesday in Toronto, as he held the Jays to just three hits over eight scoreless innings.
"He made a ton of good pitches and competes like a maniac. He does that in every start," Cardinals manager Tony LaRussa said of Carpenter.
He did not get a decision against the Diamondbacks back on June 13, but is 4-0 lifetime against them with a 2.36 ERA in 10 games, nine of which have been starts.
Carpenter will be trying to help the Cards get back on track after a rough weekend against the Royals, who denied St. Louis a series win with a 10-3 win on Sunday.
Rookie Jaime Garcia (7-4) had his worst outing of the season, lasting just two-plus innings and giving up five runs on four hits and two walks. Albert Pujols and Colby Rasmus each slugged home run No. 16 of the season for St. Louis in the loss.
Arizona will send its ace to the hill this evening as well in righty Dan Haren, who is 7-6 with a 4.65 ERA. Haren lost his second straight start on Tuesday to the New York Yankees, who reached him for three runs and six hits in seven innings.
Haren's last win came at the expense of the Cardinals on June 12 and is a perfect 4-0 in four starts against them with a 3.72 ERA. Drafted in the second round by the Cardinals in 2001, Haren has already beaten his former club twice this season.
Arizona managed a rare road win on Sunday in St. Petersburg, as Gerardo Parra hit the game-deciding two-run homer, and Rodrigo Lopez pitched six innings of two-hit, one-run ball, to help the Diamondbacks top the Tampa Bay Rays, 2-1, in the finale of a three-game interleague set.
Lopez (4-6) put forth a strong effort despite walking five batters along with three strikeouts and picked up his second straight win.
Rusty Ryal tripled and scored on Parra's second homer of the season during a pivotal fifth frame for the Diamondbacks, who took two of the three games in the series.
However, it was just Arizona's third road win in its last 19 games.
The Diamondbacks have split their six games with the Cardinals this season.