SAN FRANCISCO -- Over the course of a season, every player goes through bumps on the field and bruises to the ego. Given the chance to erase a fraction of the negative statistics, they would gladly take the do-over.

Players are stuck with their numbers, though, whatever the reason for a slump. One bad day can ruin a month's worth of good days.

Maybe, suggests D-backs' manager A.J. Hinch, stats are a little more straight forward.

"In a game built around numbers, it changes dramatically and very quickly," Hinch said. "Over the course of a season, though, things have a tendency to even out. For all the line drives that are caught, you get a few bloop hits. The composite numbers are what they are."

Take Thursday's starter Dan Haren for example. He's allowed five runs in each of his last two starts and seen his ERA grow to 3.02 from 2.79. While that's still among the top 10 in the NL, given the opportunity to erase a couple of his poorer efforts would mean the difference between 10th and fifth in the league.

He still has a chance to slip below 3.00 with a good effort against Tim Lincecum in a matinee meeting that marks the end of National League West competition for the D-backs for the year.

Doug Davis, who took the loss in the series opener against the Giants on Tuesday night, took a 3.13 ERA into the All-Star break, but then went in the other direction. His ERA has climbed to its current 4.19, the highest its been since his first start of the season.

Relief pitcher Esmerling Vasquez got off to a poor start, but was able to recover and bring his ERA to 3.49 two weeks ago. He allowed more than three runs once in 52 outings and yet has a 4.50 ERA.

"He worked for two months and pitched great and then it gets ruined in one outing," said Hinch. "Starters are different. They get 30 starts. It's hard to have bad luck for that long."

Meanwhile, Hinch made it official that Daniel Cabrera, who has a scoreless streak of six innings over his past four games, will start Saturday's game in Chicago.

"If he's efficient enough, I could let him go up to five innings," Hinch said. "He's thrown up to 50 pitches, but we can stretch that a little to the 70-80 pitch range knowing he's not going to have to bounce back."

Pitching matchup
ARI: RHP Dan Haren (14-9, 3.02 ERA)
Haren will be making the final start of what has been an outstanding season for him. He should easily have more than 14, but he has been done in at times by poor run support and also has watched the bullpen give up some of his wins. In his last outing against the Padres, Haren allowed five runs on nine hits over six innings. All five of the runs came in the fifth inning as the Padres managed six hits and took advantage of some poor defense.

SF: RHP Tim Lincecum (14-7, 2.47 ERA)
This is expected to be Lincecum's final start of the season. The reigning National League Cy Young Award winner has lost three games in September, more than he has dropped in any calendar month during his brief but successful career. This has happened despite the respectable 3.60 ERA Lincecum has posted in September. Lincecum made back-to-back starts against Arizona in April, pitching eight shutout innings and striking out 13 in a no-decision before yielding one run in eight innings and striking out 12 in a Giants victory.

Tidbits
Justin Upton is the only active D-back with more than one RBI against Lincecum. He's also made the best contact against the NL strikeout leader, batting a cool .353 against him (6-for-17) with two doubles and a triple. Eric Byrnes has had moderate success against Lincecum with three hits in 10 at bats. ... At the other extreme, Stephen Drew and Chris Young are both hoping to break out against the defending Cy Young Award winner. Drew is 3-for-23 (all doubles) and 10 strikeouts against him while Young is 2-for-25 with nine strikeouts. ... Giants outfielder Fred Lewis seems to like facing Haren, hitting .421 (8-for-19) against him while Aaron Rowand and Randy Winn have had their struggles. Rowand is a .133 hitter against him and Winn is a lifetime .171, with 11 strikeouts, against Haren. ... Cabrera will be looking for his first big league win since Aug. 9, 2008, against the Texas Rangers while with the Baltimore Orioles. He's never faced the Cubs. ... The D-backs are 19-9 in games started by Haren. ... Drew has hit safely in 34 of the 40 games he's batted leadoff.

Tickets
 Buy tickets now to catch the game in person.

On the Internet
 MLB.TV
 Gameday Audio
•  Gameday
•  Official game notes

On television
• CSBA

On radio
• KTAR 620, KSUN 1400 (Español)

Up next
• Friday: D-backs (Billy Buckner, 3-6, 6.59) at Cubs (Tom Gorzelanny, 7-2, 4.70), 11:20 a.m. MST
• Saturday: D-backs (Daniel Cabrera, 0-5, 6.07) at Cubs (Randy Wells, 11-10, 3.18), 10:05 a.m. MST
• Sunday: D-backs (Doug Davis, 8-14, 4.19) at Cubs (Ryan Dempster, 11-8, 3.51), 11:20 a.m. MST