Lincecum: Odd man out in playoffs?

Before the season, if I had told you Tim Lincecum might not make the Giants postseason starting rotation, you’d probably assume it was due to injury, not underperformance.

But as we approach September, Lincecum is struggling to find a level of consistency and his erratic starts might make him a liability if the Giants make the playoffs.

Two years ago, Barry Zito was left off the postseason roster completely due to poor performance.

I don’t think the Giants will take the same drastic measures with Lincecum, but if the playoffs started today, it wouldn’t be crazy to see the Giants go with a four-man rotation of Matt Cain, Madison Bumgarner, Ryan Vogelsong and Zito, with Lincecum available out of the bullpen.

While Lincecum’s 4.87 ERA during July and August is better than Zito’s 5.13 ERA over the same span, the Giants are 6-3 in Zito’s starts. They are 5-6 in Lincecum’s July and August starts.

Right now, Zito gives the Giants a better chance to win. In September and October, when every win means so much, team record in a pitchers start can’t be overlooked.

Over the season, Lincecum has just nine “quality starts,” which translates to at least six innings pitched while allowing three or few runs. Zito has 13.

Let’s take a look at each pitcher’s 2012 number against National League playoff contenders:

Vs. Los Angeles Dodgers

• Lincecum: 2-1, 2.55 ERA over 17 2/3 innings
• Zito: 1-2, 3.44 ERA over 18 1/3 innings

Vs. Cincinnati Reds

• Lincecum: Has not faced Cincinnati this season
• Zito: 0-1, 1.50 ERA over 12 innings

Vs. St. Louis Cardinals

• Lincecum: Has not faced St. Louis this season
• Zito: 1-0, 2.70 ERA over 6 2/3 innings

Vs. Pittsburgh Pirates

• Lincecum: 0-1, 16.20 ERA over 3 1/3 innings
• Zito: 1-0, 4.50 ERA over 12 innings

Vs. Washington Nationals

• Lincecum: 0-2, 13.50 ERA over 7 1/3 innings
• Zito: Has not faced Washington this season

Vs. Atlanta Braves

• Lincecum: 0-1, 5.40 ERA over 5 innings
• Zito: 2-0, 1.20 ERA over 15 innings

Total:

• Lincecum: 7 starts, 33 1/3 innings, 25 ERs, 6.75 ERA
• Zito: 10 starts, 64 innings, 19 ERs, 2.67 ERA

San Jose Mercury News columnist Tim Kawakami took a look at the difference between Lincecum’s numbers when he pitches on four days of rest and five-plus days of rest. To summarize, Lincecum pitches best when he’s had five days of rest.

He has a 3.97 ERA with an extra day of rest. When he pitches on normal rest, his ERA is two and a half runs higher, at 6.47. If the Giants believe in these numbers, they could be useful because the Giants might have an off day or two between the end of the season and the start of the playoffs.

Right now, I’d give the ball to Zito in a Game 4. Amazingly, he’s more reliable than Lincecum.

The Giants two highest paid players are duking it out for the last rotation spot in the playoffs. I don’t think that’s how Brian Sabean drew it up before the season.

But the good thing for Lincecum is that the season isn’t ending today. The Giants have 34 games left, which means Lincecum has six or seven starts to figure things out and make himself someone that Bruce Bochy and the Giants can rely on in October.