Endangered species: NFC West left tackles

The Arizona Cardinals showed Sunday they could protect the passer better than expected, at least for a half, without their injured starting left tackle.

Two other NFC West teams might need to do the same.

Seattle lost left tackle Russell Okung to a knee injury late in the Seahawks' 20-16 defeat at Arizona. Earlier Sunday, St. Louis lost left tackle Rodger Saffold to a neck injury. There was no word yet as to how long each player might be sidelined.

As the chart shows, NFC West teams have invested considerable draft capital in the position.

San Francisco's Joe Staley started all 16 regular-season games for the 49ers last season, plus two playoff games. He missed seven games in each of the 2009 and 2010 seasons.

The 49ers are the only NFC West team with continuity on their line.

Seattle started a rookie right guard, J.R. Sweezy, and appeared to pay a price through protection breakdowns against blitzing linebackers. The Rams finished their opener with different players at left tackle, left guard and center. Arizona played the same five Sunday, but both tackles were making their first career starts at the position.

2012 NFC West Projected Starting Left Tackles