As he watched from the sideline, an admittedly painful experience after losing his starting job because of an injury, Alex Smith believed things would eventually work out. He just didn't know where.

"I had no idea where my opportunity would be, where it would come. No idea," he said. "I guess I did have faith that it was going to come at some point, that I was going to get another opportunity. Didn't know where or what, but I was determined to stay ready and continue to work. So when it did come, I'd be ready. When this came up, I jumped on it. This was a no-brainer for me."

The no-brainer was in Kansas City, where the Chiefs in March traded two draft picks to the 49ers after Smith had lost his job last year to Colin Kaepernick. As Kaepernick went on a roll and got the 49ers all the way to the Super Bowl, Smith mostly suffered in silence, realizing he'd have to pursue the rest of his career elsewhere.

Turns out the wait was worth it.

Smith is off to a 3-0 start, he hasn't committed a single turnover and the Chiefs' resurgence has been remarkable coming off a 2-14 season.

"I just appreciate it," Smith said. "I've been through a lot, and you appreciate the opportunity to be one of 32 guys to get to do this and know how fragile that is and not to take it for granted. So you bust your tail every single day, every week. You've got to go out there and prove yourself every week. That's the bottom line in this league. You're only as good as your last game."

Patriots: Tight end Rob Gronkowski and wide receiver Danny Amendola (groin) did not travel to Atlanta on Saturday and will not play Sunday night against the Falcons, a source told ESPN.com.

Gronkowski has looked good in practice the past two weeks, but his inner circle would like to ensure that he is fully recovered from his five surgeries in the past year -- four on his forearm, one on his back in June -- before he plays again, according to sources.

Newsday (N.Y.) contributed to this report.