Arguably the weakest area for the Raiders last season was the play of the offensive line. It wasn't entirely their fault as they were playing in a system to which they were not adept - the zone blocking scheme. So, the team switched back to power blocking in the hopes of revitalizing them. But it doesn't end there.

This project will require more than a change in scheme. It will require some players to execute that scheme. Two of the Raiders' starters from last season are set to become free agents - left guard Cooper Carlisle and right tackle Khalif Barnes. Last year the team brought both back on one year deals. There is less chance they do the same again this year.

Whether the team does indeed allow Carlisle and/or Barnes walk will depend very much on who they are able to sign in free agency.

Here are the offensive linemen who top the Raiders free agent wishlist:

OT Gosder Cherilus, 28, Lions

Cherilus was in the top ten in pass efficiency among tackles (96.3) last season but it was his run blocking that was lacking. With some higher profile tackles on the market, he could wind up being a steal for a team like the Raiders who are looking to upgrade their right tackle position.

"Gosder Cherilus has been the Lions' starting right tackle since being drafted in 2008," said Sean Yuille of Pride of Detroit. "There have been moments where he was briefly benched because of a dumb penalty or inconsistent play (most recently in 2011), but that wasn't an issue last season. He had by far the best year of his career... The Lions have Riley Reiff ready to enter the starting lineup, so they can afford to lose Cherilus."

OT Eric Winston, 29, Chiefs

Winston performed considerably well in the Texans zone blocking scheme two seasons ago and his size (6-6, 305 pounds) and strength make a switch to power blocking a non-issue. The 5-year stalwart starting tackle came as advertised for the Chiefs and shored up their glaring Right Tackle issues. He allowed just three sacks all season long. He also hasn't missed a start in six seasons (103 straight starts overall).

If he joined the Raiders, not only would he be able to play for a rival of the Chiefs fan base he referred to as "sickening and disgusting", but he would also be placed alongside his former Houston linemate, Mike Brisiel.

OG Kevin Boothe, 29, Giants

Boothe was drafted originally by the Raiders in the sixth round of the 2006 draft out of Cornell. He spent one season with the Raiders, starting 14 of 16 games that season but was released prior to the next season. He immediately caught on with the Giants and has been with them for the past six seasons including both Super Bowl Championships. He started the final nine games of the 2011 season at various positions along the line to help the Giants to another Super Bowl victory.

The former Ivy Leaguer has shown incredible discipline as evidenced by his not having committed a penalty since the 2010 season.

"Boothe started at left guard for the Giants for the entire 2012 season and played well," said Edward Valentine of Big Blue View. "He isn't a great player, but he's better than I thought. Not a road grader or a perfect pass blocker, but a good lineman. He can also play center, which adds to his value."

OG Geoff Schwartz, 26, Vikings

Despite outplaying starter, Brandon Fusco, in Minnesota, Geoff Schwartz has been relegated to backup. He allowed just four pressures on 84 pass blocks and also posted high marks as a run blocker. The Panthers originally drafted him in 2008 and he was a full time starter by 2010 where he graded out very well at both guard and tackle. He is a California native, having grown up in Los Angeles, so playing closer to home could be enticing for him.

"Schwartz was brought in as a free agent after he missed the entire 2011 season for Carolina," said Christopher Gates of Daily Norseman. "The idea was to have him come in and compete with Brandon Fusco for the starting right guard spot, but the "competition" ended when he got hurt during training camp and had to have abdominal surgery... Schwartz seems to be equally adept at pass and run blocking."

OG Louis Vasquez, 25, Chargers

Vasquez was the San Diego Chargers' best offensive lineman last year and our No. 13 ranked guard. He's a solid pass protector and he graded at +8.6 with a PBE of 97.1 that ranked 22nd at the position. Perhaps most impressive is his ability to avoid penalties. He's committed only one in his four-year career, and it came in his rookie season back in 2009. If there's a knock, it's that he hasn't graded positively as a run blocker in two years, but for a team looking for a dependable player who won't make many mistakes and should be above average in pass protection, Vasquez fits the bill.

OG Donald Thomas, 27, Patriots

Thomas has shown well when called upon in a backup role with the New England Patriots the past two years, and it may be enough to garner interest around the league. His last starting job was in 2009 when he graded at +5.3 as the Miami Dolphins' right guard.

In 2012, Thomas showed his versatility by filling in at various times throughout the season. He got the nod at right guard in Week 2, posting a +1.6 grade before getting called upon to start at left guard five times in a six game stretch where he graded at +10.9. His ability to play on either side will only increase his value and he may be in line for a starting job somewhere in 2013.

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