Offensive lines that could turn fantasy studs into duds

The obsession with skill players is real.

They're the ones who accumulate the fantasy points, so basic logic has it that they should get 100 percent of the attention when it comes to predicting production. This isn't the case. A weak or strong offensive line can dramatically change the output of a team's skill players.

Did anyone see DeMarco Murray's monster season coming in 2014? Probably not, unless you knew how good Dallas's O-line could have been that year.

On the other end of the spectrum, Indianapolis' inability to address its offensive line issues a season ago was a major factor in Andrew Luck's underwhelming performance prior to his season-ending lacerated kidney.

Realizing which teams have significant holes on their O-lines can go a long way into making safer fantasy decisions. Here are four questionable offensive lines that could hurt the fantasy value of their team's skill position players:

Player grades are courtesy Pro Football Focus and are based on the 2015 season. Players are graded based on their performance out of 100. The grading system goes as follows:

90+ = Elite
85-90 = High Quality
80-85 = Above Average
70-80 = Average
60-70 = Below Average
Under 60 = Poor

Seattle Seahawks

Projected Starting Five: LT Garry Gilliam (36.7), LG Mark Glowinski (49.9), C Justin Britt (37.4), G Germain Ifedi (rookie), RT J'Marcus Webb (44.6)

Average 2015 PFF Grade: 42.2

If you watched Seahawks games last season, you probably noticed a recurring theme: Russell Wilson running for his life. His ability to scramble hid how bad this offensive line really was. To make matters worse, Seattle lost LT Russell Okung - the only stable lineman in the unit - in free agency.

There's still some risk in drafting Wilson, but he and his receivers should still be okay. The running game has serious question marks with Marshawn Lynch having retired in the offseason.

Thomas Rawls was excellent last year, but there's plenty of risk involved in drafting him in the third round, considering he could very well be in a timeshare with Christine Michael. It's best to steer clear of Rawls, considering there probably won't be consistently big holes created by the offensive line.

Two of Seattle's three divisional opponents, the Cardinals and the Rams, have great defensive lines. That's four games out of 16 where this O-line will really struggle.

Denver Broncos

Projected Starting Five: LT Russell Okung (72.1), LG Max Garcia (64.3), C Matt Paradis (73.1), RG Ty Sambrailo (36.5), RT Donald Stephenson (34.5)

Average 2015 PFF Grade: 56.1

It's ugly to imagine how the Broncos' starting quarterback - expected to be either Trevor Siemian or Paxton Lynch - will routinely deal with a collapsed pocket in Denver. Even though they are both talented receivers, it's best to avoid both Demaryius Thomas and Emmanuel Sanders in all drafts.

In Gary Kubiak's zone-run, play-action, bootleg-heavy offense, the running game is always the X-factor, but never more so than this season. The good news is that the left side of the offensive line (where the majority of runs will go) shouldn't be that bad. Regardless, there is still plenty of peril involved in drafting C.J. Anderson in the third round.

The scheme is usually friendly to running backs. Just ask Justin Forsett, Arian Foster and Steve Slaton. Anderson has a sky-high ceiling, but also a basement-level floor.

Chicago Bears

Projected Starting Five: LT Charles Leno Jr. (39.7), LG Cody Whitehair (Rookie), C Ted Larsen (37.6), RG Kyle Long (61.1), RT Bobby Massie (47)

Average 2015 PFF Grade: 46.4

Have you ever watched Jay Cutler deal with pressure in his face? It's not pretty. He tends to throw off his back foot, trusting his arm too much, and forcing the ball into the hands of his primary receiver. You can expect plenty of that this season.

The only offensive player you can fully trust is WR Alshon Jeffery. Cutler can be trusted as a matchup-based, bye week fill-in, but nothing more than that. WR Kevin White has all the physical tools to be a No. 1 WR, but after missing his entire rookie season due to injury, and being the No. 2 option in a potentially conservative offense, there's heavy risk involved in drafting him.

Head coach John Fox has historically been a very conservative head coach. Defense-first by nature, his offenses (excluding Peyton Manning-led units) have largely been very conservative.

You might think this favors RB Jeremy Langford, but he has just two career starts under his belt while averaging 3.6 yards per carry on 148 attempts last season. It's best to steer clear of Langford. The Bears are expected to be trailing in many games and will likely have to abandon the run at times.