Perhaps Chico Corrales isn’t the only guy who needed his medical attention lined up for the weekend. The Oakland Tribune’s Roger Phillips on the challenge facing new 49ers starting QB Alex Smith when the Colts visit San Francisco this afternoon at the place they used to call Candlestick.

As we assess what Alex Smith is contending with as he prepares for his first true taste of the NFL, consider the following numbers: 0, 22, 2.

The first is the number of times Indianapolis Colts quarterback Peyton Manning has been sacked this season in 114 pass attempts.

The second is the number of times he was sacked in 597 attempts as a rookie starter in 1998.

The third is the number of times Smith has been sacked in 13 pass attempts in limited duty this year.

The limited duty ends today as Smith (above), the prize rookie of the 49ers (1-3) and first overall draft choice, makes his first NFL start.

As luck would have it, the start will come at Monster Park against Manning’s Colts (4-0), who not only have a dangerous offense but also have allowed the fewest points, 26, of any team in the league.

Unfortunately for Smith ” not to mention former starter Tim Rattay ” 49ers passers have been sacked this season roughly once every 10 times they drop back, 28th in the NFL in that category.

It’s going to be difficult for the 49ers to improve in this area today, facing a Colts team that is second in the NFL with 15 sacks, four by last year’s sack leader, right defensive end Dwight Freeney.

Coach Mike Nolan has said neutralizing Freeney will be key today. But for the second straight game, the 49ers will be without injured left tackle Jonas Jennings, who would have lined up across from Freeney. Anthony Clement, who was beaten badly last week by Arizona’s Bertrand Berry, is expected to start in Jennings’ place.