Alex Smith: 'What's changed?'

Alex Smith understands more of the 49ers playbook than Troy Smith.But he had a more difficult time grasping why coach Mike Singletary told him Monday that he -- and not Troy Smith -- would be the starting quarterback Sunday against Seattle."It was definitely my first question, 'What's changed?'" Smith said. "That was definitely something that was on my mind." Singletary told Smith that he was making the move because he thought Smith gave the Niners the "best chance to win." But in response to Smith's question -- what's changed? -- Singletary told the media that something has indeed changed: Defenses have caught up with Troy Smith, who has completed 48 percent of his passes and compiled a 55.7 passer rating in leading the Niners to one win in his past three starts. "Troy playing those five games that he's been able to play there are more teams that understand that 'This is really what he does,'...