Rod Smith is Rod Smith. He was, he is, and he always will be Reliable Rod, Steady Smith. I don't expect a pro bowl berth again, but I expect him to continue performing like he's performed for the last couple of years. Also, remember that while he's been losing a step for a couple of years now, he more than makes up for it with dedication, work ethic, desire, and experience. He has never missed an offseason workout in his career- a feat that Shanahan has called UNHEARD OF. While he's getting a bit slower, remember that it was just two years ago that he chased Julius Peppers 106 yards to set an NFL record for the longest INT return that DIDN'T result in a TD. Also, while Lelie gets all the recognition as a deep threat, Rod Smith actually had the longest catches on the team for two years running (72 yards last year, 85 the year before- Lelie's career long is 60 yards). His after-the-catch skills are PHENOMINAL (I believe only Terrell Owens has more YAC over the past 6 or so years).
While your team is probably in trouble if Rod is your WR1, I don't expect he'll have any problems putting up another top-24 finish, making him a solid WR2.