San Francisco and Philadelphia are two of the NFC's best teams, among the favorites in their respective divisions (either them or Seattle and Dallas, respectively). But both have suffered significant setbacks to their offensive lines that could negatively impact their chances.

The Eagles, certainly, have had the worst luck. They lost Pro Bowl mainstay guard Brandon Brooks to an Achilles injury before camp even started. Brooks has missed a total of 6 games in the last seven seasons, starting every game and going to the Pro Bowl in each of the last three seasons. They brought back longtime left tackle Jason Peters, replaced this season by last year's first-rounder Andre Dillard, with the idea that Peters would move to guard to replace Brooks.

But Dillard -- who on Wednesday drew praise for his work at left tackle from Doug Pederson ("He has really stepped in and embraced that role") -- tore his biceps and was placed on injured reserve yesterday. He's done for the season. Nothing official yet, but most likely they'll move Peters back to his former spot. Peters is 38 and in decline, but they don't have a better option. Matt Pryor, drafted in the sixth round two years ago, will probably be next man up at guard. He'll be making his first career starts.

Philadelphia still has two of the league's very best linemen in center Jason Kelce and right tackle Lane Johnson. The other three spots look below-average, at best, knocking them from our top 10 lines.

Other news and notes:

In San Francisco, the team was hoping to have center Weston Richburg (pictured) back from knee surgery at the start of the season. Richburg isn't elite but is an above-average center. But he's expected to open the season on the PUP list, and will miss at least the first six games. Ben Garland -- re-signed to a minimum-type deal earlier in the offseason -- will fill in.

That's not the only negative for San Francisco. We factor in blocking from fullbacks and tight ends into our rankings, and it looks like San Francisco will be without Kyle Juszczyk for at least the start of the season. He's considered week to week with a hamstring injury. That's most likely to hurt the team's blocking in the running game, as well as an outlet receiver for Jimmy Garoppolo (he's averaged 25 receptions the last two years).

Saints left guard Andrus Peat is probably a top-10 player at his position, and he suffered a broken thumb in practice. It's possible he can play with the injury, but not certain. If he misses the start of the season, Nick Easton would fill in; that's a downgrade. With some players, their grades are lowered due to either injury risk or if they're expected to miss time; that's the case with Peat in this update.

Current rankings are below; colorful table with each player's grade can be seen on our Facebook page.

2Las Vegas
3New Orleans
6Green Bay
8San Francisco
9Kansas City
10LA Rams
11Tampa Bay
15New England
16LA Chargers
22NY Giants
29NY Jets

--Andy Richardson