Mark J. Rebilas-USA TODAY Sports

The 2013 NFL regular season is 19 percent complete. In other words, there's a lot of time left on the clock. Still, it's almost enough to blow my football mind when I stop and look at who Pro Football Focus (subscription required) currently has graded as the top offensive tackle in the entire league:

That's right, Doug "The Disaster" Free of the Dallas Cowboys is currently ranked first among 80 tackles who have taken at least 25 percent of their team's snaps.

In the same area last season, Free ranked 66th out of 88 qualifying tackles after somehow being penalized 15 times, which was more than any other offensive lineman in the game. The year before, he was one of only six tackles in the league charged with surrendering 10 or more sacks.

The point is that he was terrible. Unbelievably bad. There are only two possible reasons why he was still on the Dallas roster, let alone in the starting lineup, when we reached Week 1 of the 2013 campaign:

1. The stubborn Cowboys didn't want to admit they made a mistake by giving Free a monster contract with $17 million in guaranteed money after he put together a solid season and a half of work in 2009 and 2010.

2. The cap-strapped Cowboys couldn't rationalize spending money elsewhere, especially once the 29-year-old agreed to take a substantial pay cut, reducing his 2013 salary from $7 million to $3.5 million.

However, again, he's suddenly looking like the reliable, versatile lineman he was as a left tackle in '09 and a right tackle in 2010.

After drawing a ridiculous 25 flags in a 28-game span between September 2011 and December 2012, Free has taken zero penalties in his last six starts.

This season, he's held his ground against some of the best pass-rushers in football, including Jason Pierre-Paul, Justin Tuck and Mathias Kiwanuka in Week 1:

Justin Houston and Tamba Hali in Week 2:

And Chris Long in Week 3:

Last season, Houston, Hali and Long combined for 30.5 sacks, and we all know what JPP and Tuck are capable of. Yes, he had some help at times, but he's been relying on that less and less each week and it hasn't impeded the rest of the offense.

Don't forget his contributions as a run blocker, either. His 4.3 run block grade is also tops in the league, per PFF. Here Free opens up a massive hole for DeMarco Murray against the Chiefs:

This is him doing the same thing after bouncing outside with a surprising amount of burst against the Rams:

What has changed? Rarely do you see peaks and valleys this extreme. A cynic might conclude that this has just been a fluky three-game stretch. Another cynic might respond by declaring that Free has only picked up his play because he's now playing for another fat contract.

The reality is that nobody knows who the real Doug Free is. Maybe he is the steady tackle we all saw for 23 games in 2009 and 2010. Maybe the big guy was just hibernating over the last two years. Maybe a light was switched on when he abruptly put together his three best games of the 2012 season when the pressure was on and his job was on the line during the final three weeks.

Dating back to last December, Free's most recent six performances have been positive. In addition to that, he seems to be getting progressively better each week early this year:

Cowboys head coach Jason Garrett thinks that late-season rotation with Jermey Parnell really had an impact.

From ESPN.com:

“He’s responded really well,” coach Jason Garrett said. “We’ve talked a lot about how we rotated him at the end of last season. He responded well to that, responded in the offseason, came back in great shape and was ready to go. He really has been impressive since the start of OTAs, really trying to take advantage of the opportunity. I think he’s working on some technical things that will help him. I think he’s playing tougher and he’s staying on blocks, both as a pass-protector but also in the run game.”

Don't forget that Free was adjusting to a new position and a new blocking scheme during Bill Callahan's first year with the Cowboys in 2012. Garrett also suggests that it may have just taken some time for him to become familiar with things.

From the Fort Worth Star-Telegram:

“When you’re working with a new offensive line coach, there are new techniques that you use,” Garrett said. “For a guy who has played a little bit, sometimes there’s some unlearning that has to happen. I think that’s a cycle and a progression that has to happen for a player, but Doug’s a smart guy. I think he understands where he is in his career. He’s developing more and more confidence, and he’s technically becoming better and better.”

All of it makes sense, and all of it points to Free continuing to be an effective right tackle for the remainder of the 2013 season.

Considering that we're talking about the man who was considered to be the Cowboys' single biggest problem this past offseason, that's reason for even the most cynical Free observers and Dallas fans to be at least slightly optimistic.