Right now the Giants have three really good pitchers and two that are not so good.
Ryan Vogelsong, Matt Cain, and Madison Bumgarner all rank in the top 15 in ERA for NL starting pitchers. The Giants other two starters, well they are polar opposites. Tim Lincecum currently has the highest ERA of the 62 pitchers who have enough innings to qualify for the ERA crown, with Barry Zito just a few spots up on the leader board in 47th place.
When Zito was putting up surprisingly good numbers to start off the season the Giants were able to cover up for Lincecum struggling, but now that Zito has fallen back to what was generally expected of him — and actually maybe slightly below what was expected — the Giants have a major issue. They have two pitchers where they have to pray for an offensive explosion to have a reasonable chance to win.
When Lincecum starts the team is 2-12. When Zito starts the team is 7-7. When some else starts the team is 29-12, a pace that would be good for 114 wins over a full season.
Here is a helpful illustration that shows the polarization in good/bad pitchers that has developed over the course of the season:
For Game Score, 50 or above is considered a quality start, above 60 is a good start and anything above 70 is pretty darn dominant. Cain’s average game score has hovered around 70, which confirms that he has been one of the best pitchers in baseball. Vogelsong has been steadily good all year; he has posted a “quality start” of 50 or higher in 10 of his 12 starts this year. Bumgarner got off to a bit of a slow start but has put together a nice run to pull his average up to nearly 60.
On the flip side, Zito has seen his game score average fall with nearly every start to where he is now below 50 for the season. Lincecum started off poorly and has been unable to put together enough good starts to pull his average into the quality area. For the season he has managed to surpass 50 in game score in just 43% of his starts and has eclipsed 60 just twice.
If the Giants have playoff aspirations, which I am sure that they will, they will need to find a way to fix the problem with the two pitchers not pulling their weight.
There aren’t any easy fixes out there. The high minors are pretty barren of quality arms that can be better than replacement level. There don’t seem to be obvious mechanical fixes that can get Zito or Lincecum back to their old Cy Young selves, plus the cost of acquiring a quality starter on the trade market is likely to be expensive in prospect talent — and it isn’t exactly like the Giants are overflowing with prospects to begin with.
The one idea that might be worth exploring now that the Rockies are leading the way is to go with a four man rotation to get more starts and innings out of the guys that are actually performing well. This isn’t likely to happen, but if two of the starters are nearly automatic losses it might be worth thinking out of the box.