I think there will be no winner here. LA Galaxy is the favorite, they are in better form at the moment (LA Galaxy is in series of 9 unbeaten games), they are the leaders in the Western Conference, but San Jose also have something on their side. First of all, San Jose have the home advantage. Then, San Jose is playing good, even they lost from Kansas City in the previous round. San Jose have four victories in the last six rounds:

18.06. Kansas City - San Jose 1:0
12.06. DC United - San Jose 2:4
05.06. San Jose - Houston 2:0
29.05. Chicago - San Jose 2:2
22.05. San Jose - New England 2:1
15.05. San Jose - Columbus 3:0

The next reason why I am thinking Los Angeles won't win is connected with the absences. It is true both teams will be handicapped, but I rate guest's handicap as little bigger. San Jose will miss Andre Luiz and Ike Opara due to injuries, while Chris Wondolowski is on international duty (Gold Cup with USA). On other side LA Galaxy will be without Leonardo and Sean Alvarado due to injuries, while Donovan is also on Gold Cup. But the biggest handicap is called David Beckham. According to the LA Galaxy coach Bruce Arena, the former Manchester United and Real Madrid star will probably miss the game due to back injury.

Finally, San Jose have a good home record against LA Galaxy in the last few years. Three victories and one draw in the last four matches clearly show that LA Galaxy have problem on this trip. Here are the results:

21.08.2010. San Jose - Los Angeles 1:0
20.06.2009. San Jose - Los Angeles 2:1
19.04.2009. San Jose - Los Angeles 1:1
03.08.2008. San Jose - Los Angeles 3:2

Considering all previous mentioned facts, I expect both coaches to be satisfied with a draw here.