SANTA CLARA, Calif. — Troy Smith's career easily could have been derailed two years ago during a frightening, monthlong bout with Lemierre syndrome, a rare and potentially fatal disease that began as a tonsil infection and progressed to his bloodstream.

He lost 40 pounds and had trouble breathing for 2½ weeks. This all happened just before Baltimore's third preseason game in 2008, and the 2006 Heisman Trophy winner wasn't medically cleared to resume light workouts again until mid-September.

Now, across the country with his new team — the San Francisco 49ers — Smith stands on a podium after a walkthrough practice as a confident NFL starter, having moved up the depth chart from third string in a matter of two months. He jumped over a pair of former No. 1-overall draft picks in the process.