Posted by ESPN.com's Mike Sando
Power Rankings: Preseason: 18. This week: 20.
Where they stand: The 49ers are 3-5 and second in the NFC West after four consecutive defeats. Their inability to hold second-half road leads against the Vikings and Colts has proved costly. Winning those games might have given the 49ers the momentum needed to push for a division title. Instead, the 49ers have changed quarterbacks, something they seem to do most seasons, and they are still carving out an identity on offense.
Disappointments: First-round draft choice Michael Crabtree missed the start of the season during a contract dispute. More significantly, the offensive line hasn't developed as expected, particularly at guard and right tackle. Right guard Chilo Rachal, a promising young prospect, has clearly regressed. While tight end Vernon Davis and others have responded favorably to coach Mike Singletary's direct challenges, Rachal looks like he could use a confidence boost. Poor play at guard and right tackle have stood out as the No. 1 limiting factors for Shaun Hill, Alex Smith, running back Frank Gore, Crabtree, coordinator Jimmy Raye and the offense in general. The 49ers are good enough on defense. Their special teams can be a strength. Fixing the offensive line has to be the top priority in the second half of the season and beyond. Losing left tackle Joe Staley to a sprained knee hurt.
Surprises: Davis has finally seen the light -- and frequently the end zone -- in his fourth NFL season. He has gone from symbolizing wasted potential to demonstrating the effect Singletary can have in challenging players to reach their potential. Davis ranks tied for the NFL lead in touchdown receptions. He is on pace for 84 receptions and 14 touchdowns. On defense, nose tackle Aubrayo Franklin has turned into a strong player against run and pass, giving the 49ers a tough defensive front. The secondary has outperformed most expectations after losing veteran cornerback Walt Harris to a season-ending injury. In retrospect, Shawntae Spencer would have beaten out Harris easily. Spencer has returned from reconstructive knee surgery to play at a high level. He was the best cornerback on the team this season, even when Nate Clements was healthy.
Outlook: The 49ers are approaching must-win territory against the Bears on Thursday night. The 49ers lack the offensive line and possibly the quarterback to become a serious playoff threat this season, in my view. The next eight games give them what might be one final chance to find out whether Smith can become their long-term quarterback. Davis and Crabtree provide ample young weapons. Gore will continue to pick up yards even though the blocking figures to remain a problem at times.