Whether you consider traffic around SAP Center a problem depends on what you are used to. Public transportation, carpooling, and transport services are all available and are recommended. If you do drive yourself, your best bet is to get there early and park at a lot not necessarily closest to SAP. You may have to walk a bit more, but you'll save many minutes being stuck in post-game traffic.

The traffic isn't too bad and they have designed the exit points pretty efficiently. I would still try to do public transportation but if you drive you will definitely not have a problem of getting out after a game.